daveak05

for throwing a bunch of scenarios at you. They could be relative, but it's probably just a bad coilpack which is common enough.

Tell the dealer to pony up the $30 and get that swapped around coilpack the hell out of there. They can easily tell if the plug is bad, although a tiny crack in the insulator could go unseen. But the coilpacks are another story. There's no way to tell if they're bad other than tracing the misfire type an then using common sense.

They want to be cheap or experiment on your RS4, tell them it's not acceptable, period.

Evil Buddha

I may give up hunting for chasing cones, just not too close to walls ;-)

bhvrdr

a dealership or tuner or shop wants to diagnose a cylinder misfire it can be very helpful to swap coilpacks first and log. You dont want to replace parts or you could actually cause an inaccurate diagnosis. By swapping coilpacks you can first log if the misfire changes cylinders. This could isolate it as a bad coilpack that you moved. If the misfire stays on the same cylinder you can then try swapping the plug (assuming it already passed visual inspection) over to another cylinder. Now you can rule out the plug for that cylinder and look at the injector. If you start replacing parts you end up replacing the coilpack, spark plug, and finally injector without having known which was faulty if any.

Evil Buddha

a joke because of all the Motoman BS on the board. Maybe the other guys but I went by the book. I may have pushed it but always within their AOA rules, and I was very careful about that.

S4iowa

Trouble shooting 101

bhvrdr

Are you seeing any misfires come up at all? If not, I would run a log on overall timing and retard for each cylinder as well as air/fuel. Start recording below and above when you get the stumble. Can you describe the hiccup? Can it be drivetrain related as far as it being a felt vibration or does it appear to be clearly engine stumbling? Do you have any audible pinging at all and how long have you had the problem?

Evil Buddha

That is exactly what the dealer said they are trying to do.

bhvrdr

but the trouble is that since they dont get to use your car for a week and forget all other cars on the bill to be fixed, you are stuck with a misfire issue until they run their second, third, fourth diagnostics. If you had to fix it yourself, you could just mess with this in one sitting and get it all worked out. I'd ask them if you cant leave it with them for a day and tell them you want them to run diagnostics on it all day. Tell them you'll pick a day they are not busy and they can dedicate the time. This way you should be able to EXPECT from them that they take the time to do it all in one day over multiple diagnostic runs and not inconvenience you on multiple visits. It's always possible that it is a part that is only on its way out and not yet failing at all times making it difficult for them to even begin finding what part is at fault. That can suck and take a bit, but it will fail if it's on its way out...eventually.

daveak05

Good to hear...bet it rewards you down the road.

daveak05

that this is fine for diagnosis purposes. But with the proviso that they diagnose the problem under that technique quickly, and not say problem solved and send the owner on his way, only to have it happen again.

Swap the parts, do the logs, keep the car a couple days, whatever to get it right. Considering coilpack induced misfires are prevalent on Audi's, they should have put a new coilpack and plug in regardless and then if the problem reoccurs at the same cylinder they can investigate further. And if not, there would be no need for further logs and diagnosis.

The way it stands, they took an educated guess with his situation, and walla!...problem returned...and he gets to deal with it in his new $70k car. I mean come on, Mike!