Silverado :: 1998 4.3L Votec Stumbles Upon Initial Acceleration
Dec 1, 2013
I have a 1998 C1500 Silverado, with the 4.3 vortec engine, with 88k miles.
Upon initial acceleration the truck stumbles, sometimes even dies when taking off. I have had the codes read, and have gotten a P0102 and a P0404. I have swapped the MAF and EGR Valve out with a known good ones from the parts store; cleaned the throttle body; looked for vacuum lines that could be the problem but can't find anything.
I have even changed out the fuel filter since the engine sounds like it is starving.
Also, the transmission doesn't want to shift unless I let up on the acceleration pedal. I can get up to about 55 MPH and the RPMs sky rocket before it shifts, and the engine begins to ping before shifting.
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My Venture LS is stumbling upon acceleration. It starts to occur around 35 mph and then continues with occasional smooth sailing. No rough idle and no stumble when coasting. I had the spark plugs and wires replaced at the dealer today and it did nothing. Fuel trim is fine, LT runs from 0 to - 5 . I replaced the MAF sensor a few months ago and all other sensors test OK on the scanner.
Also, I took my car to the dealership to have the plugs and wires replaced and they used the after market wires named Xact. I have never been to a dealer where they used aftermarket parts. I thought that they were required by GM to use their parts?
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The car takes off from a stop as it should. However, it shifts hard from 2nd to 3rd gear and that's when it stumbles and doesn't want to accelerate. It'll go if you press pedal at least halfway down. It runs great other than that. It only has 60k.
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Bought my first Hyundai, a 2013 Accent last Saturday. Love almost everything about the vehicle.
It is equipped with the EcoBoost which I can turn on and off.
Noticing when I accelerate almost every time there is some initial acceleration and then a noticeable power loss. It's much worse when I'm accelerating through a turn.
Honestly it's hard to tell too much of a difference with the EcoBoost and AC off.
Also noticing the car really surges at times with the cruise control on. Obviously if I hit an incline it's going to boost a bit, but sometimes even on very minor inclines or straightaways the RPMS just fluctuate more than they seem to need to.
Wondering if this is normal for this engine and something I need to get used to. Coming from a Honda Civic I didn't experience this consistent power loss / fluctuation.
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I have had my 2010 Prius 2010 for a year now. I have been taking my Prius to a full service car wash with the conveyor belt. They have always seemed ver Prius savvy. But the last couple of times, after getting in the car and driving away, the car seemed to hesitate upon initial acceleration. Then the problem goes away.
The last time I took it to this car wash, I sat in the car, because I only needed the express exterior wash. About a third of the way through, the instrument panel said "Low Traction Battery... put into Park" I did not obey the warning because I was afraid of putting it in Park while the conveyor belt system was pushing my Prius along. So I ignored it. By the end of the car wash, the engine had shut down. I had to start it up and drive out, and I got that same momentary, initial hesitation as I accelerated, like before. The hesitation went away after that.
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I am 2nd owner of 98 Ford Explorer Eddie Bauer V6SOHC. Vehicle is almost showroom condition w/ 70,000 miles and properly maintained.
Problem: engine seems to stumble quite frequently and is most noticeable when ambient temp is above 60*. Highway speeds , 40MPH doesn't matter. RPMS drop but it has completely shut down only twice in the last 9 months.
There are no codes. Plugs and wires changed several months ago, fuel pressure checked by Ford and it's ok, injectors cleaned at dealer, MAF seems ok so I am at a loss. Since there are no codes diagnostics don't work. Except for the issue above, this is a very nice reliable vehicle.
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This noise sound as if an electric motor going off for a second only. It almost sounds as a CD changer changing cds but for a second only.
What is weird is that it only sounds when the car has been off, turn it on and I start accelerating to about 8-10mph. If I come to a complete stop at a stop light and accelerate again it will not sound. If i come to complete stop and put the car in park or N, it will not sound. You will only hear it on the first take off when the car has been off.
I would also like to point that I have manually shifted and this does not change a thing. The noise still comes on around 8-10mph even if I keep it in 1st gear.
Furthermore, I would also like to point out that the noise is is not loud. Chances are I will not hear if I have radio on at low levels or the A/C fan in mid to high.
Again, the sounds seems to come from the outside the cab and it sounds like an electric motor going off for about one second only.
The car is a 2012 l4 with about 60k miles on the odo.
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I just had my front axels replaced. The Cv's were clicking. That problem was fixed.
Metal clunk at initial acceleration and hard braking (none during steering)...
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Just rejoined this Ford gang after years absence. Used to own "The Muny Pit", a '79 F-150 4WD monster with a '69 429... constantly breaking something. Anyway, where to look on my '08 F-150 XLT 4WD with a 5.4, 83,000 miles. Searched the search bar for my title and found a post on an '00 Expedition describing similar issue than mine... for about 6 months now when I accelerate either from stop or a crawl; forward or reverse; more so when turning, but does do it wheels straight.
Upon initial acceleration I have this horrendous rumble / shudder in the truck, like the grinding metal bearing sound/feeling felt when the pinion bearing went out on my '79 (only felt it seconds before the 9" rear pumpkin exploded). Once rolling it stops. I have checked all wheel bearings.. I have check all the suspension joints... everything looks fine, no obvious issues. The only suspension mod I've done is a 1.5" leveling kit when brand new. On the Expedition two replys suggested changing the transmission/transfer case fluids claiming it cured their vehicles.
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I was just curious what the best way to increase initial acceleration from a dead stop is for a 2009 F- 150 XLT with a 5.4 V-8.
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I have an issue with extreme high initial idle at start up. I took my 1998 Ranger with a 3.0L to the local dealer to have some work done about a month ago. Long story short, my number six plug wire got burned against the exhaust rail.
Anyway, I guess they re-flashed the computer to the newest *.bin, or flash version. After that when I start the truck the tachometer jumps up to 2200 - 2300 RPM and then it settles down to about 1500 after a moment or two, then it finally adjusts itself to about 1100 for a few more seconds and eventually ends up at 900 - 1000 RPM.
I confronted Ford about this and they said that Ranger's and F-150's do have a tendency to do that at start up. Ordinarily I wouldn't be too concerned, however I believe that the 2200 - 2300 RPM high idle at start up at 0 F, a bit much.
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After almost an entire year of trouble-free running (with the exception of replacing a ground strap), my 2009 accent decided to start bucking and shuddering again. It only does this when warmed up, runs perfect cold. In the last 16 months, I've replaced the plugs, coils, battery, PCV valve, and ground strap. Car starts with zero hesitation.
Strong battery and starter, consistent output from alternator. After @5 miles, the car stumbles on acceleration, and idles sporadically. While looking at it tonight, I noticed a few exhaust brackets under the car had broken, and the flex section of the intermediate pipe had torn open. Could this presumed exhaust leak be causing the crap running performance?
My "exhausted" brain thought it could cause the O2 sensor to misinform the ECM, resulting in the P0300 code I pulled...
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So I have a '98 cavalier with the 2.2l and 4sp auto. Anyway, it runs great when dry conditions, but when its wet from rain or any moisture it runs terrible. It stalls and stumbles and the cab fills with a gas odor. I changed the coil packs and plugs and wires and it still does it. I have a P0301 cylinder 1 misfire detected and a P0200 injector circuit problem. I'm having a hard time believing this because it runs fine most of the time. Is there something else I can look at that is feeding this problem? Is this a common ocurrance?
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I have a 04 FX4 scab with a 5.4L and am having issues with it idling rough, and low power and stumbling upon acceleration and cruising speed. I did a scan and the codes show lean run condition, misfire on cyl 4, etc. I changed injector and coil on #4 and it seems worse. Scared to change the plugs, until I can leave the truck down a day or two in the event that I break one or more.
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2001 Hyundai Elantra, with an automatic transmission.
1. I am experiencing a "grinding" sound upon my initial acceleration from park? This only occurs when the car has been sitting for a decent amount of time and the engine is relatively cold. To give you more detail: I start the car, throw it in gear and begin to accelerate. The grinding sounds is almost instant and sounds horrible. It is fairly consistent how long it lasts and generally once the car shifts to 2nd or 3rd it goes away. I do not hear it again until I park, leave the car for a while, then start it up and begin driving again.
2. I am hearing a "tension" like noise, also a little like scraping, when I brake at slow speeds coming from my driver side front wheel. I recently had my brakes replaced so I know its probably not the pads and at the time the rotors looked fine too. It is not a constant noise during the breaking either meaning, I apply the breaks, i hear it for a second, then it goes again, then it comes back, then goes away. Again it sounds like a mix between scrapping metal and tension.
What it could be, what I could look at on my own or how to get it resolved?
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I had been driving around for a few days and the car had been feeling a bit sluggish on initial acceleration and there was also a very slight backfire.
Just seemed to have lost some crispness. No fault codes thrown with VAGCOM.
Found one of the Camshaft Hall Sensors loose. I have had this before with the exhaust cam sensor but this time it was the inlet one. The bolt just comes a bit loose and the sensor can swivel around very slightly if you move it with your hand.
It seems to be enough to upset the the performance but not enough to throw any codes - after all it is still working perfectly sending a signal as far as VAGCOM is concerned.
Just need to nip it up again with an M5 Allen key and you are golden. One with a ball end makes it easier to get to. Just regained about 20 HP
Pic for information ....
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I've got 120,000 on my 08 manual Accent. Recently I've been getting white smoke after running it hard. It happens like this. I slow down from 70mph or so with the clutch engaged to about 40mph, then upon acceleration the engine stumbles and white smoke pours from the tailpipe. My guess is a leaky head gasket.
I had the dealer go through it. They pressure tested the cylinders and put a scope in them. They claim nothing is wrong with the engine.
I mentioned since they can vouch for the engine now, I'd like to get an estimate on trade in value. I don't think I want to keep it much longer.
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I have a 2001 Acura MDX automatic transmission that at least once a day when driving around town, will suddenly loose power, RPM's seem to be stuck at 2000, and then surge up to 5000 with no forward motion. When I try to accelerate again, the car "stumbles" forward until the RPM's settle back down to between 1-3 and the car drives normal. This is creeping me out...any thoughts? Valves have been adjusted.
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My 02 F150 4.6 has 84K miles on it, and started stumbling/hesitating during accellartion about three weeks ago. Before this problem started (about 2,000 miles ago), I installed a new fuel filter and air filter. Since I noticed the problem, I installed new plugs. The problem didn't go away, so today I checked the fuel pressure. At idle the pressure is 32psi with the vacuum line left on the fuel pressure regulator (30-45 is normal as per Chilton's), and 42 with the vacuum line off (40-50 is normal as per Chilton's). I also had someone else rev the engine so I could observe, and found that the fuel pressure went as low as 28 when the engine speed was quickly increased. The standing fuel line pressure is 30 (30 is normal as per Chilton's) Does this sound like a fuel pump problem, or is there something else that I'm missing.
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I've got a misfire problem with my Focus. It started about a month ago and did not trip a code until last week. It stumbles on acceleration between 2,000 and 4,000 rpms. It is only a slight stumble and although noticeable, it does not impede driveability much. Last week I was able to get it to finally trip an OBD code. P302 - Cylinder 2 misfire. I changed the plugs and wires with no effect. I thought I had it narrowed down to the coil or injector until my wife noticed a new wrinkle.
Under normal driving conditions the misfire is annoying, but my wife found that if she turns on the A/C, it is undriveable and will not accelerate past 30 mph without some patience and a neck brace for the bucking. My first thought was the A/C compressor was freezing up. I turned off the A/C and left the blower on and it would not stop missing. I turn off the blower and it smooths right out to the annoyance I described first.
Right now I drive the car without A/C and blower whenever I accelerate. If I'm going a steady speed, all is well and I can run the blower and A/C.
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2001-F150 5.4 Eng. bucking/stumble. I think my problem is slightly different than what I am reading about. Here is what I get (125k miles):
* Engine only bucks/stumbles intermittently and not at idle or at harder acceleration (this bucking is really harsh and makes the truck feel like a learner trying to drive a manual transmission and it is jumping down the street). The engine stumble is not a regular timing such as a cylinder going out and staying out for a period of time. It is quite a random pattern to the jumping
* Originally thought it was humidity related, but now I realize it happens in any climate
* No stumble in neutral at any rpm... only at a stop if I put it in a power brake load.
* When the stumble shows up, it seems like the throttle is around 10-25% (my best guess)
* Sometimes goes days without issue, but sometimes every ride and virtually every acceleration.
* Normally no stumbling at highway speeds, unless going up a hill.
* Every time it stumbles, it can be eliminated by either backing off on the accelerator some, or hitting the accelerator harder.
* No engine codes or CEL has ever come on
* Fuel mileage appears to be the same before and after the trouble started
Here is what I have done to try to correct it:
-> Fuel related (bad gas)... tried to run the tank as close to empty and fill it with fuel from different stations... when this didn't work, I have added HEET to it to dry up any water in tank.
-> Fuel delivery... replaced the fuel filter... seemed to work for one day, but then the gremlins came back.
-> Fuel delivery... ran multiple injector cleaners through tanks of gas.
-> Intake... replaced the filter.
-> Electrical... I don't believe this is related, but my battery died... parts store tested the system and stated the alternator was bad... replaced it, and took the old one to the parts store for bench testing and it was 100% OK... even thought the old showed OK, I left in the new one as a precaution. Only other item was a set of plug changes around 30k miles ago... I think I put in the super duper Bosch plugs with a lifetime warranty.
Current thinking and items I don't understand:
A) The bucking is so severe, it appears to be a random harsh loss of either fuel or ignition. A component that has failed electrically should give me a fault code with this level of severity. No trouble codes or indicators to electrically sense this disturbance...
B) For the fuel path, the most likely item is bad gas and I emptied my tank by running it as close to empty as possible and then used different gas and HEET to eliminate water. THIS MIGHT STILL BE THE CAUSE???
C) Another one for the fuel path is an intermittent fuel pump electrical connection or a weak pump from a pressure point. But if this is the cause, then why does it dissappear upon harder acceleration?
D) One last fuel thought is injectors... perhaps one or more have a range of delivery that they don't work properly... but this doesn't make much sense as at idle and harder accels are fine
E) From an ignition standpoint, perhaps I have failing COP's. I have not just gone out an replaced them due to my limited budget and the difficulty I read about changing them. Again, if one of these is failing in an either open or short condition, the computer should set a code for a misfire for the related cylinders. I get nothing. Hence my hesitation in making this change so far.
One thing i don't understand from the various posts is that the cops can fail under loading. what makes this happen as electrically, i don't think they can detect a load or not? it is hard for me to also understand why my truck would allow me to back off on the throttle or hit it harder and the issue disappears.
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