I know there's like a thousand questions about the misfire, but mine is just a little bit different.... so here it goes:

2 months ago bought a 2005 S4 Cabriolet. 100k miles. The plugs (not the coils, but the plugs) were replaced less than 5 months ago.

I am getting a misfire on cylinders 1, 2, 3, AND 4 (8cyl vehicle).

Other than a rather "loud" startup, the engine runs great. I notice absolutely no performance issues.

CEL always flashes when I come to a stop, and remains constant on when driving. Clear the light, and it will come back on usually within the first 5 miles.

Checked the plugs, and they seemed just fine.

The car does seem to get crappy gas mileage (apx 17mpg) but not sure if this is norm, since my last Audi was a 6 cylinder.

HOW can I be getting a misfire on 4 cylinders at the same time, yet not have a single performance issue or anything else causing a red flag? Is the fact that it's cyl 1-4 (all on the left side) an indication of something more?

(Note: I have pulled the coils on both sides, but never switched them. Don't want to replace all 8 if someone has a better suggestion first).

You guys are the best. Thanks in advance.

 

its probably the coils. Very very common problem, so common in fact that I think some people get the dealer to replace them under a recall.

 

Ok switched coil #1 with coil #5. Didn't get any codes for about the first 30 minutes. Then once again started getting misfires on 1,2,3, and 4. NOT getting it on 5, the one I just switched. AGAIN, the engine DOES NOT seem to be actually misfiring at all. Sounds and runs great in fact.


So, I'm thinking that maybe it isn't the coils afterall. Maybe replace all 4 of those plugs (even though they were just switched out 5 months ago)???

 

Um, sorry, I know the last time you posted in this thread was a while ago, but, generally speaking, an engine code for MISFIRE can occur without you physically being aware of it. A miss can be anything from an intermittent interruption to the electrical system to fuel delivery problems, so you have (had?) the right idea by going to the plugs first.

Contrary to popular belief, I'd recommend standard, copper-core spark plugs, like NGK or possibly Bosch. Platinum-tip and similar plugs are great for longevity, but don't really work 'better'.

At any rate, yeah, plugs first. If the codes are cleared and it still shows up, then there's something up with either the fuel or the fire. Someone mentioned coils going bad as a common source of problems, but if it's always one bank then I'd look for control modules or similar electronic components (as an example, sometimes manufacturers will use igniters or charge assemblies to provide a similar function to a capacitor for each bank, I'd search for a single point of failure for that bank and go from there).