Accent MC (2006-11) :: 2009 - Code P0300 / CEL Came On And Stayed Over Multiple Startups
Feb 24, 2014
Had the CEL come on twice in the last few days. The first time, a restart of the car took it away. The second time, it came on and stayed over multiple start ups.
With Torque Pro and a bluetooth OBDII dongle I read: P0300 - Powertrain, Random/Multiple Cylinder Misfire Detected
From the Internet:
Possible causes
- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure
I wish it wasn't so broad... But, as the car is about to hit 60,000 miles, I plan to replace the spark plugs (NGK), engine air filter, cabin air filter. Just had the timing belt done last week. I will check all of the intake couplings for tightness.
For others who use Torque, what other settings could be useful in pinning down this issue for me? I cleared the CEL this morning; it didn't come back yet.
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I have a 2007 Hyundai Accent GLS. I just got it from a used car dealership (local) and it runs perfectly. It had a misfire code when i first got it, for all cylinders plus the p0300. It went away when i started the engine again, and didnt come back til a month later (Now). now it wont go away.
I went to advance auto and had them use their OBD2 reader for a trouble code and i got p0300, p0301, p0303, p0304. No other codes present.
I am not feeling anything bad, and from what I am told, a misfire feels like a hard shift. This is of course after getting the plugs and wires changes as well as an oil change. Standard preventative maintenance.
The mechanic used OEM parts got from local parts shop. i think the OEM plugs are the copper ones. I would have preferred iridium as they arent that much more expensive but I don't want to pay for another plug change.
The only symptoms I can think of, is that according to google, I should get around 380 miles to a full tank (11.9 capacity, 32 mpg city). I am only getting 280 from full tank to gas light.
I have also gone through a lot of oil. I checked the dipstick and it was below the low line, so i bought a quart of high mileage oil (same exact brand and type of oil that i gave to the mechanic to use) and it went to just above the full line. This was at around 1500 miles after oil change.
After visiting multiple sites about misfires, i found a few things that caught my attention. One is a site called auto service professional, which talks about the OCV for the MC accent. A lot of sites also recommend gaping the plugs at .035.
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I am trying to get a 2009 Sonata NF with a 3.3L V6 to run correctly and i have tried everything that i can find and still get the problem. The car runs very rich with a strong gas smell. The engine runs rough but doesn't stall. The car has has period where it runs fine and then the issue returns but is in more frequent and steady now. The car will run for the first 5 minutes great if it is cold and it also runs good at full throttle and the check engine light went off during hard acceleration which seems consistent with getting too much fuel. I bought a BlueDriver to read the codes and I love the data it provides but I am learning all the features.
For a little history the car has 95,250 miles. At 81157 miles the check engine light came on and an independent shop replaced the downstream O2 sensor and the light has been off for 2 years until coming back on recently. The code showing was a P0300. The shop replaced spark plugs and the manifold gasket with and oil change for $775. The check engine light stayed off for about a month and 550 miles. The car was taken back to the shop and they replaced the rear O2 sensor for $429 . The check engine light was off for a couple of days and then returned with the P0300. It might go a couple of days without a problem and then it would return.
This is when I got the car and started reading all the forums i could for possible causes. I saw the Tech Bulletin on the Variable Valve Timing Oil Control Solenoids so i replaced both valves. The check engine light returned with a P0303 for cylinder 3 misfire so i figured it was a coil so i replaced all the coils. The P0300 code returned. I check fuel pressure after seeing a post about fuel pressure regulators causing the problem but the pressure was correct. I changed the Mass Flow Sensor figuring it was getting too much gas but no improvement. I bought the BlueDriver so I could see more than just the codes. The O2 sensor looked erratic so i changed the front upper O2 sensor.
I found the Tech Bulletin about the O2 sensors fuel trim readings and realized there was an upper sensor on the back manifold and it was reading -18% so i changed it and now I don't know which way to go. I currently have the P0303 code confirmed and P0300 pending. With the live data the items that looked strange at idle were O2 Sensor Bank 1 Sensor 2 steady at 99.2% and Calculated Engine Load a 21.6%. The freeze frame data from when the light came on has all the short fuel trim at 0.0% and long term at -0.8% for both banks. Calculated Engine Load was 45.9% even though I was trying to drive slowly at 29 mph. Mass Air was 21.71 g/s, I had been running 3 minutes from a slightly warm start, Absolute engine load was 44.3%. Anything else to check or data I should look at?
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I have a 2000 Impala with a 3800 V6 series 2 with 165,000 miles. The only code I had was a P0300 Multiple random misfire that occured off and on at first, Worse in the city Better on Highway. It would start running on half the cylinders and bogged down, with the check engine light flashing, after getting onto the highway it would straighten itself out at first. I thought i had water in the gas so i ran some heat through it. straightened out for a day then happened again so I thought maybe a should run some premium gas in it, The car ran like total crap until the premium was gone, so i thought maybe it's running too rich, I put 87octane in it and it ran great for a day or two, then it gradually got worse to where it would not straighten up on the highway, tried to die at stoplights and i had to drive it with 2 feet to get it home and park it. I've replaced the battery, spark plugs, wires, ICM checked good, coil packs are good, replaced fuel Pressure regulator, looked for arcing on the spark plug heat shields and it will not start. It turns over but doesn't try to ignite and when I get the slightest rumble of ignition, it backfires up through the manifold and I see a puff of gas or light smoke by the exhaust manifold.
The car had a vacuum leak around the intake manifold cover gasket and a leak on the fuel rail. I pulled the fuel rail off my impala, snugged up the rest of the intake bolts then disassembled the fuel rail, flushed it out and cleaned the injectors the best i could, then reassembled it. before i re-installed the fuel rail I hooked it up to the fuel lines outside of the engine and tried to start the vehicle. all injectors had a nice spray pattern. So i installed the rail and it still didn't start but it had more combustion than before although it's still backfiring like before. Checked the fuel pressure by turning the key on and the fuel pressure went to zero very fast. I blew the rail out with air so to make sure i didn't damage the regulator I replaced it with the old one, ran the test again with same results, so i reinstalled the new regulator. I performed the fuel pressure test a few more times while moving the fuel hoses and when i moved the back supply line the vacuum loss stopped then dropped to zero when i let off of it. So I replaced the fuel line connector and O-rings on the injectors. It no longer has a vacuum leak.
I cleaned the EGR Valve out and had no luck there, then I removed the Idle Air Control Valve-pushed the pintle in, re-ionstalled it and WooHoo! it started! Although it still ran like crap with the same random misfire I was still happy to hear it start.I pulled the plugs on it to do a compression test and all 6 cylinders have between 180-190psi so the engine is in good condition mechanically. I installed new plugs before getting the car restarted and when i removed them for the test they were covered in thick black soot after running for roughly 15 minutes max.
I have (2) 2000 Chevy Impala's so I've swapped sensors from my wifes car to see if it would fix it. I've tested the following MAP, MAF, IAC, coil packs and ECM. None of these made the car change. I believe it is a timing chain because the car has never had a new timing chain and is way overdue, but I haven't had a code for a crankshaft position sensor. Can the timing chain be bad without throwing a code? It's not out of time enough to change the valve timing because I had a good compression test but its not firing right and still has the multiple random misfire. I have not checked or received a trouble code for o2 sensors, crankshaft position sensor or cam sensor. Something has the timing retarded and is dumping extra fuel into the engine because my new plugs looked like they were in the engine for a year.
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My 03 Chev Avalanche is giving me a P0300 code (multiple or random misfire). With no distributor or individual coil is this something I can fix myself or is it shop time?
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Mystery issue with my 2001 Accent GSI (5-speed manual, 1.6 L). I'm getting a P0300 error code and the Check Engine light (the light is like an old friend, I miss it when it's not on). This happened four months ago and I replaced the ignition coil - seemed to fix things - but now the light and the error is back with a vengeance. Car stumbles and runs rough. Changed the plugs and plug wires, but no difference.
BTW, there's a small pin hole in the upper part of the gas tank (just enough to give it a gassy smell when the tank is full) but I don't think the hole would be big enough at this stage to cause the check engine light to come on in the same way it does if you leave the gas cap off or loose.
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My girlfriends 2007 accent as thrown codes p0300 and p0302.
After reading everything I could find, I had coil pack on my list of possible problem items.
The car sat in the driveway yesterday and when she went to start it today, she couldn't get it to.
I got it to start when I got home by giving it some gas while turning the key, but I don't want to drive it anywhere.
The hard start is leading me to believe it's the coil pack.
I was going to start with changing the pcv, spark plugs, and run fuel injector cleaner through it because those are the cheap possibilities...but now may add in a new coil pack.
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Car was taking 3-4 seconds to turn over when I started it one night. After that, flashing CEL and then CEL stayed. Car idles ridiculously rough, thought it was just a coil pack but seems to be a lot more. What is going on with my car?
Performance mods:
APR intake (stage 1&2)
SPM track edition turboback
Stage 2 revo software
R8 coilpacks and NGK plugs put in 9-10k miles ago
Have 52k miles on the car if that matters
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I took my 2006 W12 to get its yearly smog check, and it will not run "air" monitors due to intermittent misfire. The code is P0300.
Any way clearing this up? (I could find no air leaks)....
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Check engine light came on. Codes are P0300, P0302, P0304. Plugs were previously changed. Plugs look good. Changed both coils. Light still one. Injectors also previously cleaned. What else should we check for? Valves hanging? Anything else to check for?
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Not too terribly long ago I got assistance on identifying and fixing an engine misfire on my 2009 Accent. I assumed was directly connected has cropped up again - a P0497 Low Purge Flow error has come up on the car.
We recently replaced the purge flow valve, and everything seems to be running fine - there is no visible cause for the error, and I've even tried making sure I get the fuel cap as tight as possible.
The code is not popping up constantly - this is only the second time it's come up since the misfire was fixed(without obvious symptoms I always clear a code once just to make sure it wasn't a computer glitch), and the first time it popped up on it's own was the day after I fixed the misfire. Need to know what to check to find out what's wrong and, of course, how much priority I should place on fixing this issue.
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My car has been really acting up lately (AGAIN) so I took it in to have it looked at and they came back and told me it had multiple cylinder misfire, and they wanted like $1200 to fix it. What in the world does that mean and what is entailed in fixing it? They mentioned doing a full maintenance on it.
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My check engine came on last night and stayed on during multiple restarts and also again this morning when I started it. I thought I was ready to bring to the dealer Monday morning but the light "magically" went off while driving today. What could cause this? And finally would there be a code stored that the dealer could check?
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Check engine light had come on, the car was running rough at idle and it would crank hard. So I threw my code scanner on it only to find out it wouldn't link. Drove it to O'Riley's and had them pull the codes. It ran rough and had next to no power on the way there. O'Riley's pulled the codes and we got a P0300 (random multiple misfire), P0301 (cylinder 1 misfire), P0302 (cylinder 2 misfire), and a P0496 (EVAP emissions system high purge flow). So once I got it back to the house, she told me that she had the codes pulled once before and that they told her it could be her gas cap so she replaced it. She also stated that she had replaced the plugs about 3 months ago.
So with new gas cap and new plugs, and these codes, I did a bit of research and come to the conclusion that it'd replace the purge solenoid. The solenoid was making a pretty loud ticking noise and when I pulled it off, it rattled so I figured that was the fix. Pulled her plugs and you can clearly see that cylinder 1 was running VERY lean and cylinder 2 was a little richer but still too lean. Plugged the plugs back into coils and laid them on exhausted. Turned the car over and we had spark. Lead me to think the misfire had something to do with the P0496 EVAP code. Put everything back together and erased the codes. Gave the car back to her and told her to let me know if the light came back on. That was Wednesday last week. Sunday she told me the light came back on and the only code that came up was the P0496 again. When I gave it back to heron Wednesday, it would still crank hard but would start.
Battery is new and checked good, alternator is pulling about 14v and checked good and the starter checked good. My dilemma is the code and the hard crank. She told me that it only cranked hard for her once so I am assuming that has gone away but we're still left with the P0496. I am not 100% sure as to how this system operates but I understand it for the most part. She told me that she had just put gas in it before the light came on. Not sure how much time had elapsed after filling it and the light coming on but I do know she put gas in it. If it's a high purge flow, that makes me think there may be a leak in the system but I'm not sure where to go from here without throwing a bunch of parts and money at it.
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We bought the car used for my youngest daughter and it had a couple of codes in it. 1st was the o2 sensor.. easy fix, grabbed an OEM one and stuck it in. Then there was the Cyl 2/ multiple cyl misfire codes that kept getting thrown.
I've seen a bunch of post about people pretty much doing the same things I started out with and still having a problem.....
1) Swapped around all the coils.. still got a #2 misfire... So, coils are good.
2) Swapped in NGK Platinum plugs with a .032 gap.... still getting misfire.
3) Replaced the crank shaft position sensor...... still misfire
4) Noticed that there was an Ebay injector in the #2 cyl...... when I pulled the plugs, that cyl was running a little lean..... bought an OEM injector to go back in there...... still getting misfire
SO, I tried using a propane torch head and putting out gas around the intake to search for vacuum leak and got no response....... so, for the heck of it, I went old school and grabbed a can of starting fluid and started spraying it on the intake around where it bolts to head... bam... found a vacuum leak on #2 cyl....... ordered an intake gasket off of ebay, spent about 3 hours on it pulling the intake and replacing the gasket,( the bolts had loosened up over time and there were small tears in the gasket allowing it to suck air) .. put the new gasket on, cleared the codes and it's been running perfect ever since.
Check for a vacuum leak where the intake manifold bolts to the head... might save time and money.
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I guess misfires are a rite of passage for these vehicles. I purchased it only a week ago. Welcome to Hyundai...
The car has 53k kms. It's throwing P0300 and P030X on all cylinders. There was one instance of P0128. The engine runs smoothly and doesn't seem to down on power, although I have nothing to compare it to. The only performance issue is that it acts as if there is a rev limiter at 6k rpm. It sputters and stops pulling above 6k. Strangely, it doesn't throw the codes under load. The light flashes while it's running steady-state.
I pulled the plugs and they appeared to be in excellent condition with no erosion of the electrodes. The ash is slightly more white than I would expect, making me wonder about it being excessively lean. I called the dealer. They told me that coils are problematic. Replacing the coils made no difference.
That lead me here. I found the thread "Check engine light flashes then stays solid," which referenced the ECM update.
Interestingly, of the codes mentioned on the TSB, the car is having all but the last two.
- P0300: Random/Multiple Cylinder Misfire Detected.
- P0301: Cylinder 1 - Misfire Detected.
- P0302: Cylinder 2 - Misfire Detected.
- P0303: Cylinder 3 - Misfire Detected.
- P0304: Cylinder 4 - Misfire Detected.
- P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature).
- P0328: Knock Sensor 1 Circuit High Input.
- P0461: Fuel Level Sensor A Circuit Range/Performance.
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I know it is a random cylinder misfire code however I started my car in the morning and it was fine I moved it and put it back in my driveway. I started it up later and waited for it to heat up i came back outside 10 min later and my check engine light was flashing and my car was shaking like crazy you could tell the engine was misfiring like crazy. I had under a quarter of a tank but not empty yet. I shut it off and turned it back on and it was still doing it. I drove the mile to the gas station the way it was.
Under partial throttle it was revving to 4500 and over 5, had to let of throttle to make the car shift up a gear. I filled up and started the car again performed fine after that however the check engine light was solid now and still on. I went to my local mechanic and he read that code P0300. I changed my spark plugs that day and they were crap the original spark plugs I have 65,xxx on my car now. Car is smooth now. I cleared check engine when i saw him first and it did not come back on all day even before i changed the spark plugs later that night. Why my light was flashing and why my car was acting like that till i filled up?
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I own a 2002 SC430 with 20,200 miles on it which I purchased new. The other day the check engine light came on. I checked it with the code reader and got the following 2 codes. P0300 (random multiple misfired detected) and C1201 (engine control system malfunction). The car ran great before, now running real ruff and when you drive it has less power.
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A few days ago my "Check VSC" warning came on along with the check engine and traction lights being on. I left my car in a parking garage for a week when I was on vacation and the lights came on once I started the car after getting back from my trip.
I have had the "Check VSC" warning before and I fixed it by replacing my gas cap. My gas cap seems fine this time around so I got my codes scanned and the only one that came up was P0300. Having this issue with the 2007 Lexus GS 350? I still feel like it's my gas cap because I bought a cheap replacement last time around.
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I have a 2006 Camry 2.4l and I'm hearing a loud noise coming from the idler pulley on cold startups when I put it in gear. I don't hear it when it's in park. The noise gets worse if you turn the a/c on. I have replaced the belt, idler pulley and top motor mount. I took the belt off and cranked it when cold and there was no noise even in gear. I can see the idler pulley moving and can confirm that's the noise but what it causing the belt to make it do that? Could I have bought a defective idler pulley?
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Yesterday I went to star my 2.0 Jetta and it instantly starting sputtering at idle. After maybe a minute of sputtering the car died. Tried restarting it and it would instantly die after starting. Car threw code P0300: Random Misfire.
As of today the car now runs again with no problems. No codes. I didn't touch a thing and it seems to have resolved itself.
The entire engine bay was wet from condensation due to temperature change. Is there any way this could've contributed to the misfiring? I'm thinking the spark plug wires might have gotten wet and that was causing the misfire.
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