Originally Posted by btm757
My neighbor has a 03 focus with a 2.0
well yesterday it threw a CEL and she wanted me to check it out. I took it to Autozone to put a scanner on it and came up with a P0171 - System to Lean Bank 1.
The lady at autozone says that normally means needs a tune up. Well I know needing a tuneup wont throw a CEL for being Lean, It would be to rich correct?
Also does anyone know of any common causes for this CEL.
Any help would be appreciated.
she is wrong.
next thing you need to do is determine which part of the fuel map (loaded or unloaded) is being compensated for by increased pulsewidth in your fuel trims. Check with a scanner the live data and see where your long term fuel trims are positive (because its adding fuel) - either at idle, or under load (like driving down the highway going 55)