P0171 and P0174

[fordpowerstroke]

HELP!!!! I have a 2000 Explorer Eddie Bauer with 133k and every 2,000 or so miles it throws the infamous P0171 and P0174 codes. It never stalls but at idle in gear it feels like it has a vibration in the engine. If you let it idle in park long enough the rpms will drop down and come back up. Most noticeable when the engine is cold it is rough like a vibration at steady throttle up to about 17-1800 rpm. No noticeable lack of power or hesitation, and it gets about 15 mpg in town and about 19-20 highway. It never stumbles or stalls, just the rough occasionally rolling/eratic idle and the vibration at slow cruise. The vibration is also noticeable in park at 1500 rpm, so it's not a transmission or u joint. SOS

 

[BrooklynBay]

Welcome to this forum! Check the intake manifold gaskets for leaks.

 

[fordpowerstroke]

I will. I've already sprayed an entire can of carb cleaner on every last ever loving hose, fitting, the upper and lower plenums, everything. Even unhooked the brake booster. NADA.

 

[fordpowerstroke]

Of course I still hold to the belief any 4.0 SOHC can be fixed for $1.99. A dollar's worth of gas an a $.99 cent lighter :-D

 

[ZWilson07]

The codes are for the system running lean on both bank 1 and bank 2.

More than likely you have some type of vacuum/evap/exhaust leak or some combination of them. Since it is affecting both banks, I would be hunting for a vacuum leak at first.

Unfortunately they can be somewhat hard to diagnose 100% without some type of smoke machine or at the very least have some type of way to monitor fuel trims and O2 readings while going around with propane, etc.

To be honest, just spraying carb cleaner all around while listening for a change is at most, a pretty poor way to for sure find all the leaks especially on OBD2 and later vehicles. You can occasionally get lucky with that route, but it certainly can be hit or miss.

Do you have a way to monitor your STFT and LTFT?

 

[fordpowerstroke]

I can have a local shop do this, I'm thinking a dirty MAF or the stock PCV valve. I will have them do the fuel trims and post the results

 

[ZWilson07]

I can have a local shop do this, I'm thinking a dirty MAF or the stock PCV valve. I will have them do the fuel trims and post the results

Unfortunately with these types of things, it could be any number of the things mentioned and if you don't have some diagnostic equipment, it can be hard to track down on your own without just throwing parts at it.

Let us know how it goes.

 

[fordpowerstroke]

Think I'll just shoot it...

 

[fordpowerstroke]

It's the 4.0 SOHC

 

[fordpowerstroke]

Also it was in a minor front end collision, would it be worth checking the vapor canister and vacuum lines?

 

[ZWilson07]

It's the 4.0 SOHC

Thanks I thought so. I went back and saw your post about 4.0 SOHC, you just got me before I could edit the post again haha.

If you have a volt meter, you could at least do some testing on the MAF on your own.

 

[ZWilson07]

Also it was in a minor front end collision, would it be worth checking the vapor canister and vacuum lines?

Well that could certainly cause an EVAP and/or vacuum leak which would in fact cause a lean condition.

Like previously posted, without taking some diagnostic equipment such as volt meter, scan tool, etc and start pounding away at some things, it is going to be hard to narrow it down to one thing. Lean conditions can honestly be caused by so many things.

Also without having a way to monitor LTFT and O2 readings, it is going to be about impossible to find a leak such as that with just propane/carb cleaner/etc, especially in the hard to reach parts of the EVAP system. A smoke machine is obviously even easier but most usually don't have a lot of easy access to one.

 

[fordpowerstroke]

I sorta remember how to do that from my days at Ford

 

[fordpowerstroke]

Given the right diagnostic tools I can fix anything, I'm hoping this is something I can find myself. I'm tired of the rough idle and at low speeds

 

[ZWilson07]

Given the right diagnostic tools I can fix anything, I'm hoping this is something I can find myself. I'm tired of the rough idle and at low speeds

Well what sort of diagnostic tools do you have, have access to, or willing to buy lol?

 

[fordpowerstroke]

On hand just a DVOM

 

[fordpowerstroke]

I have access to a Bosch scan tool as well

 

[ZWilson07]

Edit:

well first thing is first, get that scan tool, and start getting some values at different loads and rpms such as STFT, LTFT, MAF, Fuel Pressure, TPS, O2 readings, etc.

Also become good friends with this link....

http://www.explorerforum.com/forums/showthread.php?p=2364255

 

[fordpowerstroke]

Okay cool thank you!

 

[ZWilson07]

Okay cool thank you! ��

You're welcome.

Also be prepared mentally that it could be quite a bit to learn and a bit of a pain in the ass to diagnose this.

It could be something simple and easy, or it could drive you insane, just fyi lol.

I dealt with these kind of issues enough in 2014 on numerous vehicles that came through, that I finally invested into a smoke machine for myself.

Good luck