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.
View 9 RepliesMy Focus has 102,000 miles. It has thrown a p0171 code and I have been attempting to fix it. So far this is what I have done:Changed MAF, air filter, PCV Valve, plugs, Valve cover gaskets, Bank 1 O2 sensor and fuel filter. All new. I have cleaned the throttle body, fuel rail intake manifold. Cannot hear vacuum leaks and tested for leaks with carb cleaner.
Symptoms: engine cranks but has a hard time starting, usually on second try. When tank is about half full I get Rough acceleration, higher RPMs (doesn't change gear) and engine stalls on hard left turns. Idle gets rough at times but usually stabilizes at around 700 rpms.
At the beginning, #1 spark plug chamber had a lot of oil in it. It's been a few months and no oil after Valve cover gasket and PCV change. Tested coils and the plugs get a spark. Before I start messing with the fuel pump, am I missing something else that I can do?
I have a 2003 F150 4.2 with 155000 miles. What may be causing this?
View 6 RepliesThe "service engine soon" light on my 2003 F150 Supercrew 4.6L (225k miles) just came on. The code it's throwing is P0171.
View 3 Replies1999 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.
View 2 Replies97 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?
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.
View 8 RepliesI 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.
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!
View 4 RepliesMy 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?
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.
View 2 RepliesI 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?
View 2 RepliesIt'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?
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.
View 4 RepliesI've got a '98 F150.throwing codd 402, excessive flow EGR, also the oil pressure drops to absolute zero only when gear shifts but comes right back up. No knocking or other distress sounds in engine. I know I'm in need of an oil change. I already searched a bit and decided to swap out the DPFE sensor which I did purchase from the dealership. No code as of yet but what could that pressure drop be? Could a simple il change and filter fix that?
View 3 RepliesMy 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.
View 7 Replies2002 F-150 4x4 super crew w/5.4..So I've got the P0136 code, horrible fuel mileage (around 7 mpg just driving to work without hitting very many lights) and the check engine light comes on intermittently, and I get that code. I have borrowed my friends scanner ("Determionator Scan System") and I can see the live data from the 02 sensors. Today I drove around for a while and watched the scanner and the H02 data, and the downstream sensor on bank 1 shows at most, .09 volts, and it also says its detecting a lean mixture. The code P0136 is for this sensor in particular, and I have heard that an 02 sensor should be around 1 volt. The downstream sensor on the drivers side showed around .75 volts at max.
I believe that it is working correctly, or close to it, and I do not get a code for that sensor. So my question is, is the downstream sensor on the passenger side (bank 1) causing the P0136 code and the poor fuel mileage? also, could an exhaust leak cause the sensor to throw a code and not be bad at all? I do have some very minor exhaust leaks, on both sides of the truck..I'm leaning towards replacing that one 02 sensor. The wires and plug connection to that sensor look fine, plus I would think that if there was a bad wire/connection it would not register any voltage at all.. I have to add, the truck runs fine overall after I replaced the intake manifolds last week. It does still idle high, around 1,000 rpm, after coasting to a stop, then after a few seconds goes back down to a normal idle of around 650 rpm. but idles normal upon starting or in park.
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.
We have a 2003 Passat 1.8t. Had the Check engine Light come on. Went down to AutoZone and hookeded up the OBDII reader. Came up with P0171, Fuel System for Bank 1 was too lean. Probable causes:
1. Fuel Pressure of MAF (If Bank 1 & Bank 2 set codes together)
2. O2 Sensor
3. Ignition Misfire
4. Fuel Injector Problem
Car has 60K - has always run well. Wife says she thinks it's running a bit sluggish. I rarely drive the car, but I think she's right. Car is not missing or running rough.
I cleared the code & started the engine; Check Engine Light is off; then looked at the codes and I find a P0171 (Pending). She tells me that the light has been on before & then gone away. So I guess it clears itself, but eventually comes back.
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?
View 12 RepliesI have an 05 Toyota corolla, and have the check engine light on, I scanned it at autozone and error code is P0171 - System Too Lean (Bank 1). Which shows following possible causes: Faulty MAF, O2, fuel injectors blockage etc. On recommendation from the guy in autozone, I added fuel additive to clean the fuel line/ injectors. The check engine light went away for 9 months. But it is back on again. Tried putting in fuel additive again but the light remains on.
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