Ford F-150 - 1997-2003 :: 1999 XLT 5.4L - Getting P0171 Code Only?
Apr 12, 2016
1999 xlt with 5.4 lt p0171 only. it started with what felt like a misfire or hesitation and rough idle. Extremely rough at 40-45 mph. but with no misfire codes just p0171 so all 8 coils and plugs and sparks replaced twice in one month. and still same code tested fuel pump pressure 28 psi.... removed clogged cats, still same code... new pcv valve and elbow.... checked for air leaks around intake and intake manifold and nothing.... cleaned mass air flow sensor...I can unplug any coil on bank 1 and it wont make a difference. But if I unplug any bank 2 coils and engine makes a difference.
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I just bought a 99 f150 and the check engine light came on with code p0171,system too lean bank 1. It runs and drives fine but has a strong smell of gas when I shut it off.
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I have a 2003 F150 4.2 with 155000 miles. What may be causing this?
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The "service engine soon" light on my 2003 F150 Supercrew 4.6L (225k miles) just came on. The code it's throwing is P0171.
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I am still battling a p0171 code on my 2000 f150 5.4. I checked the fuel pressure at idle it sits at 31. I remove the vacuum line off the regulator it goes to 41. When i give it throttle when in gear it will maintain at 30. And when I shut the vehicle off completely it will maintain 38. Just looking to see if this is correct numbers. I was trying to determine a weak fuel pump.
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97 F150 4.6 200xxx on recent rebuild. My truck is throwing P0171 & P0174.
I think I tracked it down to leaky IAC and EGR gasket. I sprayed both with carb cleaner and the RPM's dropped.
My question is, wouldn't the RPM's rise instead of drop? I was under the impression that they would go up if the gaskets were leaking. Or did I use the wrong spray?
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97 F150 4.6 Vin 6, 5-Speed Trans, 200,000mi, Rebuilt recently. I was on my way to get my truck smogged, but she threw a code, P0171. I read somewhere to clean the throttle body elbow, which I did (needed to do it anyway). After I had everything put back together, I start her, and it's rough and immediately dies. If I keep the RPM's at about 1.5k for a minute, then let off, the truck will run fine for about 30-45 seconds, then die again. I just replaced my IAC and the problem persists.
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I had my fuel system cleaned by the dealership last weekend and I feel like I gained 50hp+ ... Now its throwing a P0171 about a week and a half later. My computer also listed P0174 under the pending codes or whatever the section was.
2003 F150 5.4L ... I cleaned the MAF sensor a couple weeks back which stopped a rough idle and I have put some 300+ miles on it since. about 200 miles since the fuel system cleaning.
I got home and popped the hood and it sounded like a vacuum cleaner. Guess it is a vacuum leak. I might need to stop using this ford house. I swear this is the second time there was a vacuum leak(I think, first time they said it was spark gap issue). I'll be heading back in the morning now.
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P0306 (ok #6 missfire) with P0171 & P0174 --- Do I chase electrical or fuel or both. Afraid to assume anything but probably would normally address the misfire electrical first.... Don't want to go down that 'primrose path' if others have been there first!
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My daughter returned from college with her 2000 f150 4.2 idling and running rough on acceleration. It is throwing a P0171 code only. I replaced the isolator bolts/plenum gaskets four years ago because of a P0171 & P0174 codes.
So far I have replaced the MAF, new PCV valve and elbow, checked all obvious lines for vacuum leaks (though I suspect a leak somewhere still). Also, a quick check of the plugs show some lean color/deposits on the drivers side only. Any thoughts or troubleshooting I should try next?
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I've got a 2000 f150 with a 5.4 and 135,000 miles. The other day it was driving fine then i stopped and got gas and after that it was boggy and running rough so i thought bad gas but i ran through that gas and got more at a different store. The cel came on i got it checked it was misfire cylinder 1 so i put new cop, spark plug, and injector. Unhooked the battery and then the light came back on so i ran the code and now im getting a p0171. I checked the pcv and sprayed around the intake and vacuum lines. I also checked the pcv hose and elbow in the back and i found nothing its a fairly new hose. So, it does run rough it shutters a lot.
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I have a 2000 f150 with 5.4 Triton with 165k miles. I did invest in a code reader. It started missing and code P0302 came up along with P0171. Put new coil on #2 and truck ran fine for a few days. Then it started to run rough again. Shaking, Idle rough, no power and CEL came on again. This time code P0171. I changed out fuel filter to no avail. My next step was to start looking for vacuum leaks. As I'm searching, All I am finding is trucks with this problem also get P0174 code. My question is since I am only getting lean on one bank does that pretty much eliminate things like MAF or the famous elbow vacuum leak and make something that only affects one bank like an O2 sensor on CAT more likely?
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It's been a long time since I have posted here mainly because my truck was wearing a bow tie for awhile. But my wife was nice enough to tell me the Bow Tie wearing truck was making a funny noise on New Years Day (seems a small drum corps took up residence in the oil pan). So anyhow now I am back in a real truck . My new to me 1998 F150 5.4 Liter ran fine until yesterday. It started idling rough and almost stalling at red lights. about halfway home the CEL light came on and is throwing a P0171 code.
So far I have checked for vacuum leaks including all the elbows on the PCV system' tried the spray test with a can of flammable break fluid and a can of starting fluid (man I love the smell of that stuff) could not find a leak. Cleaned the MAF sensor and the K&N air filter (not a fan of these) IAC seems to be working. Only thing I know that is leaking for sure is the driver side exhaust after the cat. But that is the wrong bank if I am correct on which bank is which.
So why only one bank running lean and why does it act like it is only firing on 4 cylinders?
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I just purchased a 2003 F250 Super Duty with the 6.8L V10 It has really high miles on it as it was a landscaping companies fleet truck. I'm sure that it was pretty well serviced as it has 300K miles on it and it's still running pretty decent.
I picked up the truck and I have to get the smog done soon. It idles with what I can only describe as a slight miss and it runs and drives great. seems to have plenty of power for the miles that's on it.
There is no active CEL on but I scanned the OBDII system and found a P0171 Lean bank 1 code in the pending codes list of the scanner. I guess this year engine doesn't have an EGR Valve or DPFE sensor because I've looked high and low for it and there non existent on this engine.
I've checked for vacuum leaks by spraying brake cleaner or carb cleaner all over the place and it makes no difference and all the vacuum lines and connections look okay.
When it's running It does sound like a vacuum leak right behind the top of the plastic throttle body but I can't find it, I don't know if this big *** engine just sucks that much air or what.
Like I said I need to smog this thing soon and I don't want it to fail if it's missing or has another issue. The fuel injectors look new and one coil pack looks like it's a replacement...
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I have a 99 f150 with the 4.2l v6 with a 5 speed 173000 miles. I picked it up not to long ago. When I first got it it had both the P0171 & P0174 lean on bank 1&2 it was also siting for a while. I replaced the fuel filter which was filled with black fuel, also changed the PCV valve, cleaned the MAF sensor, and changed the oil. I cleared the code, drove it for a little bit and the light came back on after 20 miles.
I then proceeded to replace the upper and lower intake manifold gaskets. Upon doing that i noticed that i was missing one of the linkages for the IMRC. I went to the junkyard and pulled off another linkage rod off the same motor. ordered new plastic clips, put the IMRC on cleaned everything up and began putting it back together. I also cleaned the Injectors while i had them out as well and put in new spark plugs and wires.
Put everything back together. code was cleared since the battery was disconnected. drove it and then the engine light came back on again. this time it was only the p0174. so i then both the upstream and downstream O2 sensors on bank 2, reset the code and it came back on again. I'm lost.
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My Explorer CEL just came on today, when checked it only brought up a code P0171. I have read through a bunch of the post and it seems most people get two codes where as I only get one. Also most say their vehicles run rough, mine runs great, so I am at a loss as to what to check or replace first. There does seem to be a slight ping when under load.
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Ok, so this past week i towed my 72 f250 to IL from CA. 2100 Miles. 6100#s with the trailer. No problems at all. Got about 9 MPG too the whole way. Ok, so here is my problem now. As some of you may know, IL just got about a foot of snow. Its all slush at this point. I am living in the country right now so i drive thru alot of it. Ok, now you know the back story, today i drove the truck to my brothers house, put it in park and bam! check engine light came on. About a half hour later i drove it to AutoZone and had them check the codes. Here is what they pulled.
P0705
P0171
Need to know what to replace. I have to drive it back to CA in 4 days.
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So I have a 1997 ford f150 v8 4.6 2w... I got codes p0171 and 174 my truck seems fine till the idle drops, it's weird when I have it on park it's fine if I turn the wheel left the idle drops when the ac turns on the idle drops and it's wasting crazy gas. Where should I start first in finding this problem?
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2001 F150 5.4L Triton Motor. Everything seemed o.k. then got the Engine Service Light. Checked with reader and above codes only appeared. Read numerous articles/videos and pulled the PCV hose/boot assembly and replaced the whole thing with oem part. Visually checked for disconnected tubing = none found. After this and with the new hose assembly in place I performed a reset. With the scanner still connected restarted engine and read values: ST FTRM1&2 = -.08~+2.3, both oxygen sensor voltages are varying and the LT FTRM1&2 hang around +26 and +28.
From what I understand the ST seems o.k. but the long term is WAY OUT OF WHACK. Started it up again and took carb cleaner spray and covered all the connections I could see = no change in engine rpm. No cracks in the air cleaner body. Big plug to the MAF was inserted and plugging the hole. I am thinking of making a smoke "machine" and trying that or removing the hoses from the throttle body and plugging the holes in the throttle body and see if that clears them up. IF it does then connect one by one and keep checking the values. Lot more work but I am at a loss.
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2002 F150 - 5.4 ... So just bought this truck about a month an a half ago. No problems but the other day the SES came on. It is showing P0171 and P0174. And P0000 (almost forgot that one) was told that's generic though. Haven't really noticed a difference in the way it's running. Has been extremely cold here in WV but the only thing I can notice (or think I notice) is the gas mileage has gone down a little. After reading some on this forum I'm looking for a vacuum leak correct?
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So, my 2003 F150 4.6 that I just put back on the road after a four month break is running like crap. I took it off the road for the winter because it was missing (no codes) and didn't feel like dealing with it then but after running it for a day the CEL comes on. It shows the following:
P0304 - hoping it is a coil pack
P0456 - pending. Gas cap?
P0171 - pending. One bank too lean?
Does the 171 code possibly have to do with the misfire in Cylinder 4? I know it is impossible to tell yet but am hoping there is a potential connection.
Before I parked it in January, it was running a bit rough and stumbled on acceleration but never would show a code. Now all this. Going to change the coil first, tighten the gas cap, check for leaks and see what happens but is there anything common on these trucks that I should also be looking at?
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