Hey guys, I have a 2003 A4 that has 107,000 miles on it. I bought it with 95k miles and instantly did the timing belt/waterpump replacement. The water pump seal was leaking a bit because the previous owner had used the green antifreeze in it at some point. The seals were apparently bad because of the incorrect coolant. I completely flushed the system a couple times after replacing the pump, seals, and everything else. I also replaced the spark plugs with the (audiforums) recommended NGK plugs correctly gapped, and I replaced all 4 coil packs. I regret replacing them with O'reily brand coil packs that I intend on replacing with OEM coil packs once I diagnose what is causing them to "foul out". Ok so now that you have a background on the engine's history here is my problem. From a cold start I have a rough idle, which is caused by random misfires in a couple cylinders (according to the cheap autozone tester), and it clears up within 10-15 seconds. I am losing a miniscule amount of coolant, and I can smell it after the motor is hot, which leads me to believe I have a leaking head gasket causing the rough idle during the initial cold start. However, sometimes from a cold start I do not have an idle issue and the check engine light will go away for a day or so. I am NOT losing/burning any oil either. The gas mileage will also vary from time to time with up to a 8mpg difference, along with the fuel economy there is a noticeable loss of power. I plan on shutting the engine off within a few seconds of cold starting it when it has a bad rough idle and pulling the plugs to see if there is condensation/coolant/whatever on the plugs. I will also try pulling the plugs before starting it some morning to see if there is any fluids in there. My question is, what do you think is causing the rough idle, and would that also be causing my trouble with the coil packs? I have went through two completely failed coil packs since buying the new ones. I don't want to buy good coil packs or replace the coil pack wiring before diagnosing the cold start issue. Thank you guys a million!!!!

 

hey korndmc, i have an 05 audi and i am having similar problems. vary rough idle for 10 seconds in the morning. after that the car runs smooth as though nothing ever happened. i have a coolant leak but not able to figure out from where. i can smell oil/coolant when the engine is hot. no white smokes. what do u think could be the problem? did u figure out what it was in ur car?