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.
View 7 RepliesI have 2007 explorer with the 4.6 V8....
Recently it started running horrible. Rough idle, drives badly, hesitation, etc. Check engine light is on, code P0171. I cannot find a vacuum leak, and i am pretty much at a loss. Before it started running poorly i replaced the thermostat, and flushed the coolant. I am assuming this is a coincidence.
2003 Sport Trac. My car was not starting, told my fuel pump, replaced twice and nothing. Found out about inertia switch and changed it, now car runs.
Before this switch blew out my car was running perfectly, no check engine, nothing. Now i have changed my fuel pump twice and put a brand new fuel filter in and soon after i get lean codes P0171 and P0174. My fuel pressure is 60psi at idle and drops to 0 after about 30 seconds when the car is shut off.
A lot of my intake is new since i did have a vacuum leak before, so i do not suspect that is it, especially since this happened after the new fuel pump. I am completely stuck as to what i should do. And i get hesitation when trying to accelerate sometimes
I have a 2003 F150 4.2 with 155000 miles. What may be causing this?
View 6 Replies2003 Ford Explorer, with P0171 and P0174 codes, common problem, as I have read. I pulled the cover over the engine off, and I immediately found the likely problem. There is a hose/connection that runs from the valve cover on the right side, about 6 inches behind the oil fill tube across and looks like it comes into the Carb. Where it turns to come into the carb is a rubber elbow. This elbow has a hole in it. Temporarily I have used electrical tape, but when I run the vehicle, I see the elbow begin to collapse. I believe the elbow is getting weak with age, plus the hole/tear doesn't work. Anyway, what i the part number, or what this is called. Hoping Advance Auto, or Napa will have it, just don't know what it is called, and can't figure out the part number. Otherwise I will pull it off tomorrow and take to advance and see if they can match it.
View 5 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 RepliesI 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 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 RepliesI 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...
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?
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 RepliesWorking on my son's 2001 sport trac. 200K miles but it has always been a great running truck.
I have two CEL codes:
P0171 System too Lean (Bank 1)
P0174 System too Lean (Bank 2)
I have found several issues so far, but have yet to get rid of these pesky codes.
So far I have changed:
- Intake Gasket - I had coolant loss which replacing this gasket fixed.
- PCV Valve and Hose - valve was damaged and the hose leaked.
- EGR Valve - Valve was leaking
- Fuel Filter
- Mass Airflow Sensor
The engine does appear to be running much smoother now, but the lean codes remain.
I have been getting a P0171 and a P0174 code lean bank 1 and 2 sensor 2. I have replaced all 4 censers the 171 is gone but I keep getting the P0174 and it only comes on when I am on the highway after driving around 10 miles or so i got a freeze frame of the data when it happen.
View 6 RepliesWhat a p0171 is?
View 2 Replies