Questions and Answers

Ford Expedition P0171 & P0174

Q. Hello, I have a 1998 Ford Expedition, 5.4 liter, 4WD, 67,000 miles, K&N air cleaner. I have been getting diagnostic codes P0171 and P0174. I have done the following to address the problem:

Replaced the PCV valve
Replaced the fuel filter
Ran several bottles of fuel injector cleaner
Inspect each vacuum line for leaks/cracks
Cleaned the K&N air cleaner
Reseat the oil dip stick
Checked the gas cap

After doing the above, I erased the codes, but the check engine light came back on after 175 miles, 4 days of driving (and with the same lean condition codes). What's left? Tear out the EGR valve? BTW, the Ford runs PERFECT! One last thing, what is "bank 1"? Is it the bank with #1 piston? The "left" side of the engine? I considered myself a pretty good shade tree mechanic, lay it on me, I'll figure it out!

Mike

A. You and about 24,000,000 other people have the same problem.

See Ford Mass Air Flow Sensors.

Bank one is the cylinder one side.

Added 11/24/02

Hello Vince, I just wanted to drop you a line and tell you how I got rid of the diagnostic codes listed below. I simply unbuckled the air cleaner, exposing the MAF. I then sprayed the two wires in the throat of the MAF with aerosol electronic cleaner. I used Chemtronics brand but I'm sure any brand of "fast evaporating" non-residue spray will do. After the spray job, I waited one minute or so for the cleaner to evaporate and reconnected the air cleaner. After buttoning up the air cleaner, I erased the codes, it's been 700 miles and the codes have not returned! I suspect I had an ultra thin coating of dust/oil on the MAF wires.

Since you mentioned (in your web site) that writers never give feedback after the repair, I just wanted to reverse this trend!

Thanks,
Mike

Thanks Mike, great tip!!!