Contour Enthusiasts Group Archives Forums General Troubleshooting help narrow down p0171 possibilities

I have read FAQs and I would appreciate if someone could help narrow down the possible options on P0171 that already cost me $500, a recurring problem with my 1996 Ford Contour GL (4 cylynders, manual), with 75000 miles on it.

The "check engine" light appeared 3 times in the last year, interestingly enough, on the same driving place and situation, as I was accelerating in 2nd gear going uphill 10% steep road at 5200 elevation.

First time it happened, my mechanic said that the error code was P0171, that it might be low octane gas and first thing to start would be to try higher octane.

Second time, he advised to replace all oxigen sensors and the fuel filter and save all sort of diagnostics.

Now it happened again, and I am wondering what it may be: lean gas? vacuum leak? catalytic converter?

Any ideas, based on when and where the problem occurred 3 times, and what we fixed so far?

The car actually seems to run fine, and I do not hear a hissing sound.

It would help me to hear:
- what are the priorities
- what is the thing that I can look myself
- what I shall tell the mechanic to try first.

Otherwise it will cost me another few hundred dollars, and I want to make sure that it gets solved.

Thank you very much.

Stefano

Get the code read again to be sure it's the same one. AutoZone will do it for free - except in California.

P0171 is a lean code. O2 or air leak is most likely the problem.

Before you spend money on the O2, double check the accordian tube on the intake tract as those can crack and not be easily detectable, then check the vac lines under the hood - particularly the hard plastic 3/4" corrugated ones near the fire wall. I had to pull mine & replace them with some regular vac or fuel line tubing. Easy job.

Good luck.

I had the same problem in my contour 2l with automatic. I couldn't find any leaks in the vaccum lines so i decided to try and clean the MAF sensor took the code out with the obd2 after doing so, the light has not come back on since, and that has been several days nows.

Bingo on the MAF sensor!

Keep in mind that altitude does not affect systems using a MAF.

Also check for intake and vacuum leaks.