I have a 2003 A4 Quatro 1.8 T
And for week my check engine comes and I have lost power on pickup, we have change the mass airflow, however the light still on, please help
code "P0171"
I should have llok at postings just found a thread on the problem, hope my is the same as every
I have checked for the vacuum hose coming off the intake manifoldone and mine is in great condition, so what else could be please advise

Check all vacuum hoses, including the "L" shaped formed one.

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2001 A4 1.8T Q Casablanca White, Tip, ESP, Xenon and Premium

I have check all the valves and everything seams to be ok, however one of the valves go bad after 50 miles and the car statrs to vibrate, took to the mechanic he changed mass airflow, spark plugs,

Here are the pictures of the valve that keeps gping bad, please help

is the car misfiring? im kind of confused by your writing... if it "vibrates" under acceleration, then youre most likely misfiring... coilpacks are an common troublemaker... you said the mechanic changed your spark plugs correct? i bet you have at least one dead coilpack.

it does not vibrate on aceleration, it vibrate on idleling once the valve goes bad and that is after 50 miles, what could be causing the valve to go bad

I have check all the valves and everything seams to be ok, however one of the valves go bad after 50 miles and the car starts to vibrate, took to the mechanic he changed mass airflow, spark plugs, but the valve keeps going bad and misfiring the car does not die it vibrateson iddling