misfire/rough idle for 10 seconds

[milan2k12]

Car is a 2004 Audi a4 1.8t fwd 4cyl.. 89200 miles. Just had a timing belt (tensioner and idler included) change along with serpentine belt, water pump, thermostat, coolant temperature sensor, coolant housing flange, coolant flush, alignment, oil and filter change (0W-40 Mobil 1 full synthetic) change ... I fill up 93 gas and yesterday I put in a fuel injector cleaner when I filled up my tank. Oh and also I changed one of the ignition coils which I had in reserve just in case one let out on me on the road like it did before on i95, and I also changed out my spark plugs and put in brand new ngk pfr6q gappd (which was in there before they just looked beat up) .. and another thing to mention when I pulled my coils out to do the spark plug change I noticed there was a tiny bit of oil on each coil, I called Audi dealer and they said its common just wipe off the oil from the coils and plugs housing, which I did. So this morning, it was a little chillier then usual 61f ..I live in Florida and we have a cold front .. OK onto to the problem This morning I go to start my car..and I always let it idle for about five minutes, and a couple of seconds into idling the engine starts shaking and the cel starts flashing .. right away I thought "damn there goes an ignition coil " because I had the same symptoms before and it was an ignition coil which is an easy fix .. but after maybe ten seconds of engine shaking and cel flashing it all stopped and everything went back to normal!! The temperature gauge went half way and I drove and everything was fine.. Given all the information and services I have done to the car in the past week ... can anyone tell me if these are beginning symptoms of a ignition coil giving out or a plug or what?? Or is it just that all the new parts aren't used to the cold temperature so they were getting warmed up? I'll keep y'all posted if this weird misfire happens again or if a coil actually goes out soon. Any help /suggestions would help! Thanks

[lyleswk]

It begs the question did the shop slip a tooth on the belt. Too coincidental...

[milan2k12]

Originally Posted by lyleswk

It begs the question did the shop slip a tooth on the belt. Too coincidental...

If that was the case ..wouldn't I experience more problems rather then that one time ten second act up?

[lyleswk]

Yes, reduced mileage and power. Having done a timing belt, tensioner, and water pump 5 times (once on my B6, once on a B2 with an inline 5, and 3 times on my turbo V6 Nissan), there is no break in with these parts. I have heard of 3 cases where a botched timing belt job on a 3.0 V6 has cased knocking / pinging at elevated RPM and reduced power which were all fixed with a return to the shop. Never heard of this on the 1.8t, but it makes sense that in the first 10 seconds, the ECU will retard the normal advance based on the knock sensor during start via the VVT. If this is true, then it will never be able to advance the timing as programmed and thus your mileage and power will suffer. Finally, just simply too coincidental that this started right after the TB job was done.

That's my 2 cents.

[milan2k12]

Originally Posted by lyleswk

Yes, reduced mileage and power. Having done a timing belt, tensioner, and water pump 5 times (once on my B6, once on a B2 with an inline 5, and 3 times on my turbo V6 Nissan), there is no break in with these parts. I have heard of 3 cases where a botched timing belt job on a 3.0 V6 has cased knocking / pinging at elevated RPM and reduced power which were all fixed with a return to the shop. Never heard of this on the 1.8t, but it makes sense that in the first 10 seconds, the ECU will retard the normal advance based on the knock sensor during start via the VVT. If this is true, then it will never be able to advance the timing as programmed and thus your mileage and power will suffer. Finally, just simply too coincidental that this started right after the TB job was done.

That's my 2 cents.

I see your point. but this only happened once so far

[turbo510]

Originally Posted by milan2k12

This morning I go to start my car..and I always let it idle for about five minutes

You're not doing your engine any favors by idling; idling is a necessary evil of internal combustion engines: they need the momentum of a turning flywheel to keep going, even when the engine isn't doing any useful work. It also takes longer for coolant and oil to warm-up at idle than when driving, which contributes to sludge. Personally, as soon as the engine fires, within ten revolutions I'm in gear and putting the gas to work.

[milan2k12]

Originally Posted by turbo510

You're not doing your engine any favors by idling; idling is a necessary evil of internal combustion engines: they need the momentum of a turning flywheel to keep going, even when the engine isn't doing any useful work. It also takes longer for coolant and oil to warm-up at idle than when driving, which contributes to sludge. Personally, as soon as the engine fires, within ten revolutions I'm in gear and putting the gas to work.

i don't let it idle for five minutes.. exaggeration. but usually when I first start my car, the RPM is above 1 so I just let it sit there til ti goes below

[Prospeeder]

Originally Posted by turbo510

You're not doing your engine any favors by idling; idling is a necessary evil of internal combustion engines: they need the momentum of a turning flywheel to keep going, even when the engine isn't doing any useful work. It also takes longer for coolant and oil to warm-up at idle than when driving, which contributes to sludge. Personally, as soon as the engine fires, within ten revolutions I'm in gear and putting the gas to work.

kind of poor advice for a turbo car. Its critical turbo cars get at least a minute of cold fast idle before being drivin. Warm starts no big deal. I would wait to see if it does it again. If its only done it once. check the code, see which cylinder it is. The oil in the spark plug wells is NOT normal. Thats the valve cover gasket leaking. And could cause misfires and coil failure.

[turbo510]

Originally Posted by Prospeeder

kind of poor advice for a turbo car. Its critical turbo cars get at least a minute of cold fast idle before being drivin.

That's news to me; I've had turbo cars of one kind or another since turboing my first Datsun 510 back in the day. The thing is, soon as you have oil pressure, the turbo's bearings and seals are as lubricated as they will ever be. Now shutdown is different; if the turbine housing is really hot from a long pull up a hill or something, run it easy for a few minutes to bring the temp down.

[daihashi]

Originally Posted by turbo510

That's news to me; I've had turbo cars of one kind or another since turboing my first Datsun 510 back in the day. The thing is, soon as you have oil pressure, the turbo's bearings and seals are as lubricated as they will ever be. Now shutdown is different; if the turbine housing is really hot from a long pull up a hill or something, run it easy for a few minutes to bring the temp down.

I'd have to agree with you. I let my car idle for maybe 30 seconds-1 minute before I go off. I just stay out of boost until I reach operating temperature.

Even on cool down, with turbos that are coolant and oil cooled... letting the turbo to cool down to prevent coking isn't as critical. This was true with older journal bearing turbos that were oil cooled only, but not so much with newer oil/water cooled turbos.