audiboi2

Hello, I've been on the forums for a while but have never posted. I did a search and am still not having any luck. I have a 1998 Audi A4 2.8Q that has a bad misfire problem. The CEL is on and flashes and has code P0300 (random misfire). The car has a new coil, plugs, wires, cam sensor's and ignition module and still misfires. Sometimes it gets to the point where the car barely runs. However I noticed that the car runs much better at freeway speeds and hardly ever misfires. But in stop and go traffic is really bad. Does anyone know what else it could be?

Thanks,
Cory

viceprp

Wouldn't be driving it if its flashing..

audiboi2

Already to late, the previous owner kept driving it that way so its already gonna need new cats.

audiboi2

bump

audiboi2

So I took it to a shop and i guy told me that the only reason its still misfiring is because it needs new catalytic converters. I'm planing to replace them tomorrow but i don't see how that can make the car misfire. Has anyone ever heard of this?

4Driver4

I'm not sure what is more silly, the idea that the "bad" cats are causing the misfire or the idea that the PO's driving with the flashing CEL means that the cats are automatically bad.

Find someone who can fix the car.

audiboi2

The cats are bad, i'm 100% certain of it. I would just like someone to give me a bit of advice on what could be the problem.

MartinH

I wish I could help with a diagnosis but I think it would be cheaper in the long run to go to a good indy mechanic and get them to diagnose the problem. Replacing the wrong parts gets expensive.

4Driver4

Change the coolant temp sensor. Get a new one at the dealer.

viceprp

Well then, change the cats and see what happens..