carguyRS4

I just bought an '07 RS4 2 months ago and haven't had a problem until just this morning. The engine started running a bit rough and hesitating noticeably. The check engine light came on so I checked the codes, and I had 4 misfires on I believe cylinders 5-8, and of course the "multiple cylinder misfire" code as well.

I pulled the plugs to change them all, and the entire driver's side of the car's plugs were carboned up, while the passenger side of the car looked to be burning normally.

Why would 4 cylinders on the same side of the car all start misfiring at the exact same time and all be carboned up?

The audi service department locally was little help over the phone, so I'm turning to the people who know their cars inside and out

ELEVENS

Each bank is controlled by a separate ECU...

carguyRS4

Interesting, I wasn't aware of the fact each bank had an ECU. What would your suggestion be, resetting the ECU? Just buy an OEM ECU, or look into an upgrade?

silverRS4

Whoaa, hold on there. Yes, each bank is controlled by its own ECU. Each bank has separate control of its respective coils, injectors, O2 sensors(with lambda control) and even camshaft adjustment as well as the sensors necessary to provide info for these outputs. I highly doubt the issue is with the ECU itself. Its more than likely an O2 sensor problem on that bank which is giving the ECM incorrect info, so the fueling in that bank is incorrect.

If you find an "upgrade" to an RS4 ECU, let me know. Maybe you can help me find an upgrade for my Rolex and my Enzo....j/k

carguyRS4

I can take the humor Good point though on the "upgrade" I'm simply going off of research that I've seen. I know APR and I'm sure a ton of other companies will just retune your ECU or whatnot.

Is there a simple way to diagnose which component might be faulty before I end up spending hundreds of dollars on parts? I just find it strange that instantaneously I have 4 cylinders misfire all at once, but I understand how the O2 sensor feeds the information to the ECU and could be the cause of a problem...

Thanks for the help!

silverRS4

I'd start by looking at fueling adaptation in Advanced Measuring Values (previously called Advanced Measuring Blocks). They can be found down in block 32 I believe. First look at bank one (passenger side and called module Engine I), then look at bank 2 (module Engine II). The adaptation values should be very low for both (less than 10%) and fairly similar bank to bank. That should give an indication if the lambda control messed up in one of the banks. The Manual that comes with VCDS explains how to look at Advanced Measuring Values. If you bought your cable on E-bay you'll just have to fiddle until you figure it out. I believe that once you select module Engine I, or Engine II, there is a button right on the screen named "Advanced Measuring Values". Its pretty simple really. It enables you do log a multitude of things that you simply pick from a list, up to 12values.

s4master1

don't start throwing parts at it just yet.
what is the mileage in the car?
If only in driver's side is misfiring is very possible to have a bad catalytic converter.
as we all know RS4s are having issues with them, which can be covered under emissions warranty up to 80k depending in which state you are.

carguyRS4

The car has 87,000 on it.

I'm not sure what the issue ended up being. I put some octane booster and injector cleaner additive in a full tank of gas and drove it on a short trip 2 hours away, and by the time I got there, the issue was gone. The engine light even went off later on as well.

Thanks to everyone for their suggestions and help...I'll be sure to check back here for updates with these cars!!

Reggie

Congrats - fingers crossed for you