SRTurbo04 Posted April 11, 2011 Report Share Posted April 11, 2011 Our 97 ford expediton with the 5.4 just broke 200k... an now its throwing a code p0171. "System Too Lean (Bank 1) very similar to code p0174 system too lean (bank 2)" possible symptoms would be dirty or fault maf or bad o2 sensors.. is there any way to test to see what it is before i start throwing money at this? Quote Link to comment Share on other sites More sharing options...
twistedfocus1647545489 Posted April 11, 2011 Report Share Posted April 11, 2011 Clean the MAF. You can get spray cleaner specifically for the job, but I have used alcohol before with okay results. If it has never been cleaned with miles that high I wouldn't be surprised to find that it's dirty. My last Mustang required a cleaning around 60K. Edit: here's a decent writeup on the procedure: http://www.berrysweb.com/clean_your_maf.htm Quote Link to comment Share on other sites More sharing options...
SRTurbo04 Posted April 11, 2011 Author Report Share Posted April 11, 2011 Ill try it..after reading into it most people say its a dirty maf or there's a line off the pcv valce that gets a hole in it. Anyone know where the pvc valve is on a ford 5.4 Quote Link to comment Share on other sites More sharing options...
mjrsplat Posted April 11, 2011 Report Share Posted April 11, 2011 if its a vac issue, its a rubber elbow on the back of the motor. iirc its a dealership only item due to diff sized inlet and outlet, but if you have rtv, a copper elbow, and the diff size hoses, you can make the part. one hose will slip outside of the copper elbow the other side will slip inside. Quote Link to comment Share on other sites More sharing options...
Patterson Posted April 11, 2011 Report Share Posted April 11, 2011 Is it whistling annoyingly loud? If it is that's the hose on the back of the manifold. Otherwise clean the maf first. Quote Link to comment Share on other sites More sharing options...
TurboRust Posted April 11, 2011 Report Share Posted April 11, 2011 I'd bet $20 on a vac leak..wanna bring it over tonight Paul? I'll show you where Quote Link to comment Share on other sites More sharing options...
SRTurbo04 Posted April 11, 2011 Author Report Share Posted April 11, 2011 I'd bet $20 on a vac leak..wanna bring it over tonight Paul? I'll show you where That would be much appreciatated but I work late tonight fml Quote Link to comment Share on other sites More sharing options...
EvoXbmx Posted April 11, 2011 Report Share Posted April 11, 2011 If it is only 1 bank with the lean code, its definitely a vacuum leak. if both banks are lean, its probably a leak between the throttlebody and MAF. I just picked up a 99 Expedition with air ride with that same engine and I am in love with it!! These trucks are so nice to drive. 177k on mine and running strong Quote Link to comment Share on other sites More sharing options...
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