2001 Audi A4 Quattro Question: code po171

I RESENTLY HAD A CUSTOMER WITH THIS PROBLEM, CHANGE THE MAF SENSOR AND THIS WAS THE CORRECTION. THIS IS GOING TO FIX THIS PROBLEM 9 OUT OF 10 TIMES. THX JIM

Check all the small vacuum lines on the top of the engine again. After 90K they become brittle and will cause the P0171 code. Using a smoke machine usually roots these leaks out but you can use a can of brake cleaner if you have it. Lightly spray around those lines and see if you can get the engine to react. Be cafeful!!!

if you have a 1.8L engine it's most likely the hoses under the manifold. I hope that helps.

You might also check for manifold leaks.