Hi everybody I have a 2008 Audi RS4 with 108KM = 68Miles. I changed the coil packs and spark plugs two months ago. I also added injector cleaner to the gas tank all within the last month. However my car still takes a while to start sometimes and cranks for a while. It sometimes idles rough for a couple seconds right when the engine ignites and the engine light comes on and it says multiple cylinder misfire and codes like p0300, p0304 and p0307. I turn them off then a about a week later same thing. Any suggestions what it can be? I already changed the spark plugs and coil packs. Thanks !!

 

I'll be honest, you may not get much traction with this here. Those are pretty generic codes and the RS4 is pretty rare (not a lot of technical knowledge about them here).

Since you already changed the plugs and coil packs, it's possible it could be a fuel problem, but you should also be getting other codes as well if that's the case.

You could also try over at AudiWorld--they have a dedicated S4/RS4 forum that seems to have some life. There are S4 and RS4 forums here too, but they are not super active.

Sorry, I hope you get it sorted!

 

I was going to add that is reads like when my diverter valve went bad, except I didn't throw codes. If I were to guess (and I am) it seems to be a fuel issue. Maybe not enough fuel pressure causing delayed starting and the shuddering at start up?

 

Do you have a ball park of how much that will cost ?

 

Diverter value is about $60 if I remember correctly and is pretty easy to replace. Not convinced that is your issue though.

 

have ya changed the fuel filter? even with using cleaner, a bad filter could cause flow issues. just my guess