I have a 2004 A4 1.8 AWD which misfires at startup for about 30 seconds. I took it to the Inskip Audi in Rhode Island and they charged me $600 to clean the injectors and replace the plugs but after 3 days I had the same problem so I refuse to take it back for more service and more money.

Here is what I know.... it never misfires when driving. I get a DTC code of P0301 or P0302 ( check engine flashes while its misfiring) when I start the car. After 30 seconds or so engine runs smooth and check engine stops flashing.

If the car sits for long periods like more than a week its fine, if I start it often its fine, Often is about every few hours. The misfire mostly happens if it sits overnight.

I also changed the all the coil packs which did nothing. Cost was $120.

One thought I had was that the #1 and #2 injector was leaking into the cylinder when parked overnight and when it sits for long periods the fuel evaporates and this is why I don’t get the misfire if its sits for long periods. Also when it sits for short periods of time I don’t have the problem is because not enough fuel leaked from the injectors.
This is only a theory and I hate to buy 2 injectors for $100 each to find out this made no sense.
Anybody have any ideas on other possible things to check???

 

Is oil leaking into the cylinders? What about MAF?

 

No oil, plugs were dry. I took the MAF out and cleaned it with MAF cleaner although it didn't seem to be dirty.