Contour Enthusiasts Group Archives Forums General Troubleshooting p0171

I have had 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 8-10% steep. This is in Salt Lake City 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, we decided 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.)

Thank you very much.

I would first check to see if there is a small vacuum leak in one of the hoses. They tend to crack at the nipples.

the code is P0171 is System(adaptive fuel) too lean (bank #1) ok good luck