i have a 2000 Audi tt 1.8 which is starting to run a bit rough. 2 weeks ago, i had a fault code for the canister purge valve which i replaced. now have check engine light on which returned the following codes: P1426 manufacturers control - auxilliary emissions controls and various misfire codes P0300, P302, P0303. Anyone know what the problem could be? i know the car is due for a tune up....would it be that simple? Please help! [:'(]

 

Change the spark plugs.

 

thanks...i changed the plugs, also fuel filter. still same misfire when the engine is cold. rpm swings up and down then stays up..maybe 100-150 rpm above normal, until the engine warms up, then settles normal and everything seems ok. At warm engine start, everything seems ok as well. After a while of driving, i get a check engine light with misfire codes on multiple cylinders. could it be a bad coil pack??? and how do i know which coil pencil might be bad if thats the case? a mechanic told me that he believes it to be another electrical problem, since i have multiple misfires and he doesnt believe that all coils are bad at same time. could one bad coil be causing multiple misfires? he thinks i should go to dealer for diagnosis and to get ecu reprogrammed??? dont really want to do that yet, as he wasnt sure of the problem anyway...hoping my friends at audiforums can save me some money.... what should i do next?