missfire

[strapper]

When starting my car and driving off getting it up to tempature after about 5-6 miles of driving it develops a missfire or stutter when driving in all gears at all differant areas of the rev range. If I park up and stop the car for 15-20 mins then drive it after that the car runs perfectly!
This only seems to happen on the cars first run of the day after it has been parked up over night.
Any suggestions as to what I'm looking at here?

[newsh]

I'd suspect the ignition, possibly plugs or coilpacks, it sounds moisture related. Pull the coilpacks and plugs and check all is clean and good.

[strapper]

how reliable are the coilpacks?

[Knight Rider S4]

What is the mileage on the car?

[macspring]

Don't forget to

Also consider either of the two ignition amplifiers on the bulkhead. Does it run on 4 or 3 cylinders for a sustained period of time when the fault occurs?

Pull off each injector's electrical connection to determine which cylinder(s) is not working?

Anyone else, as I am not too good at this?

Best of luck with it.

Kind regards.

[UrS4boy]

Any suggestions as to what I'm looking at here?

Suggest you have a look at this procedure to help you sort out your ABY ignition problems:

http://forums.audiworld.com/s4s6/msgs/149788.phtml

The overnight thing is bothersome because it implies that there is some kind of leakage or oil or water that may be infering with the spark plugs.

But if you go through the procedure, starting in morning, removing the coil pack to inspect the plugs and boots, you might find your answer very quickly.

Dave F.

[strapper]

The car has done 147K miles. The car isn't missfiring at idle only when the throttle is applied, possibly only when the car stars to boost it missfires so it could be quite hard to find which plug/lead it is unless I replace all of them?

[UrS4boy]

The car has done 147K miles. The car isn't missfiring at idle only when the throttle is applied, possibly only when the car stars to boost it missfires so it could be quite hard to find which plug/lead it is unless I replace all of them?

You really need to go here:

http://forums.audiworld.com/s4s6/msgs/149788.phtml and go through things methodically. Coil to plug boot connectors can be had out of the US for $5 each plus shipping (buy 10). Suggest replacing them just to eliminate them from further enquiries. How are the plugs? Have you checked for a weak coil? (You need to check these things)

[strapper]

I am also going to check the fuel filter as that could also be another suspect?

[mdm]

sounds like the coil packs to me, mine did the same, missfires going into boost, works ok the rest of the time. the coil packs are a service item at 100,000 miles.

[ericd]

mfts, no cold start mode ?, only ever does it when it's cold ?, what kinda temp does it run at normally ?

[strapper]

how much are they roughly?