QuestionQUESTION: I have a 2003 A4 Quattro 1.8 Turbo. A few weeks ago I got a code P0456( I think), I cleared it and it never came back, but no fixes were performed. Last week after driving for an hour my engine started to randomly misfire. I proceeded to change the spark plugs and the coil packs. It is still misfiring. I can drive the vehicle on the highway at high rpms, but it feels like the engine is sluggish and has lost power. At low rpms(1K) it will start sputtering and have to keep it revved high. Is it possible I have a MAF issue or a leak that I should check for? I even checked the wire harness for the coil packs and it all looks good. No mods have been performed to this vehicle. Any help would be greatly appreciated.
Regards,
Jose
ANSWER: Could be the MAF or a TPS. Also check for vacuum leaks. I would do a compression check just to be sure. Let me knwo what you find, Jan
---------- FOLLOW-UP ----------
QUESTION: What is a TPS? Do I need to take it to a shop for a compression check or can I buy the stuff to do it. Thanks Jan for yoru invaluable help.
Jose
ANSWER: TPS = Throttle Position Sensor. Compression meters can be bought fairly inexpensive; most autoparts stores will have them. Check the ground connections on the coil packs too. Let me know, Jan
---------- FOLLOW-UP ----------
QUESTION: I checked the MAF. Checked the TPS. Checked coil packs and compression. All is fine. It will drive normally while it is in Drive, but as soon as I place it on park it will misfire. Get codes P0171 and P0507. Any more ideas?
AnswerThe engine is getting air from somewhere; the idle control cannot adjust the idle, so it is throwing an error. Check the idle control module itself Check the intake system very carfully for cracks or splits; especially between the butterfly (operated by the gas pedal) and the intake manifold. let me know if you find anything, Jan
