Hey Guys,

Came across the site the other day and was absolutely impressed with all the great contributions! My 1999 expo E.B. just threw the code P0174. I found a lot of great discussion on these threads, but only when BOT P0171 and P0174 were thrown. Since I only have the one code, does this narrow down my possibilities, or should I just look at all the things for both?

 

I'd first look at your long term fuel trims. Bank #1 could be just a whisker away from setting the P0171 code. If bank #1 is not close, your looking at something that only affects bank #2. Maybe an intake manifold runner leak to bank #2, a bad fuel injector o-ring on bank #2, a lazy injector on bank #2, etc.

If bank #1 is close to setting a lean code, look for something that affects both banks - maybe the MAF is dirty, the fuel pressure is low, a vacuum leak after the MAF sensor, etc.

Also, look at the freeze frame data. If the code set at higher RPMs and under load, that could signal a fuel supply issue. If the code set at lower RPMs and under closed throttle that would indicate a vacuum leak issue.

 

I'd start looking for an intake leak on the driver's side.

 

I just had the same happen with the P0171 code on mine. Hit the MAF with cleaner, reset the light and it's been running great since.

 

how do u reset the CEL ?

 

With the code reader, or remove battery cable for a few minutes. Code reader preferred.

 

new here. i have been reading here about this code and i learned a lot. thanks to all here giving advice. my truck just popped out this code...but with none of the rough idling....etc. my gas mileage has never been greater. nothing unusual at all. good pickup....a lot of power....no usual symptoms like described here. but....last winter i started to smell exhaust. i took it to Cole Muffler and they told me nothing was wrong. saw no problems at all. (another words....you are a silly woman!). then i started to hear a faint ticking on drivers side when accelerating. i went to PepBoys and they said pretty much the same as Cole. i am not nuts!!!!! i know my truck! now, this code popped up, and only this code. the manager at PepBoys said it could be a sensor, MAF (which i had already cleaned with CRC), intake leak, plugs or coils (i already replaced these and all was new). i told them i think it has to do with an exhaust leak and (after owning Ford trucks forever, and replacing this....) its the EGR tube thats leaking. (i got the look, 'yeah, right!'). so they put it on their diagnostic machine and all my sensors are doing what they are suppose to do and even the egr valve is working fine....but....the egr tube has a hole in it!!!!!!! ha!!!!! told them so!!!!! fixed tube, code is gone....check engine light is out!
so...if i may add to the causes of this code....P0147...and only P0147...please consider the EGR tube. its a pain in the butt and if it leaks, your Check Engine light can turn on with the P0147 code. i may be a woman, but i know my truck...and i love my truck!

 

That's the way to stick to your guns ...especially for a woman.