Knife

I posted this over in the VAG-COM Forum too, but, I'm just trying to cover as much ground as I can so, apologies if you've seen this or answered it over there.

My 2004 S4 (35,500 non-abusive miles) started running very rough, like it was missing or starving for fuel or something.

I ran VAG-COM and got the following error codes:

"VAG-COM Version: Release 409.1-S

Control Module Part Number: 8E0 910 560 A
Component and/or Version: 4.2L V8/5V G 0020
Software Coding: 000XX8822
Work Shop Code: WSC 25663

6 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
16686 - Cylinder 2 Misfire Detected
P0302 - 001 - Upper Limit Exceeded
16687 - Cylinder 3 Misfire Detected
P0303 - 001 - Upper Limit Exceeded
Intermittent

16690 - Cylinder 6 Misfire Detected
P0306 - 001 - Upper Limit Exceeded"

I assume this means I've got an ignition problem. Either plugs, or wires, or coils.

Can anyone tell me, from looking at those codes, anything more specific? Like, where should I start looking - Plugs? Coil packs?

Also, just in case I want to go that route, the care is recently out of warranty, anyone have an idea of how much it would cost to bring it to Audi for the fix? If it's not like, half a million dollars, I just might let them diagnose and fix it.

Thanks in advance.

S4iowa

A test could be to remove and change the order of the coil packs to see if it moves with the change.

<img src="http://pictureposter.audiworld.com/126448/engine.jpg">

Knife

Thanks for the suggestion.

I changed the plugs and moved all the coils around today and the car is still randomly misfiring on a bunch of cylinders. Some the same as previously, some different.

That, along with the fact that this all just started happening suddenly and the misfires are completely random make me think it's not one or a few coils.

Could it be an ignition problem that is further "upstream" than the coils?

Maybe fuel, fuel filter?

I'm kind of half-wondering if this is Audi/the car's way of telling me I am past my routine service interval. Like, maybe the ECU is programmed to start cutting out regular ignition if you don't get the service and reset after some time, so that you have to limp it into the dealer.

zeusrotty

could be cats... did that to me...