My 2001 996TT has an occasional misfire which I notice on idle. So I thought I would connect the Durametric software and monitor the misfires in the individual cylinders. I drove the car for about 35 minutes.
In that time I got..........................................
4 misses on cylinder 1
0 misses on cylinder 6
1 Miss on cylinder 2
2 Misses on cylinder 4
15 misses on cylinder 3
4 misses on cylinder 5

The misses occured during acceleration and idle. Whilst driving the car you wouldn't know as it drives fine. I only notice the odd miss when it's idling.

I've already changed the DV's, boost hoses, the plugs are fairly new. The only thing I can think of is the coil packs, they are probably 8 years old and the car has 44k miles on the clock.

Is there anything I haven't thought of ?

NO CELS

 

I think 8year old/44k coil packs could be the problem. While you are in there, i would suggest you laso put new plugs. What plugs are you running?

 

+1 for coil packs.

 

The standard Beru's are in there. I think I will change them to the recommended Bosch ones.
I think its the coils too but just wanted some other opinions before I shell out for 6 coil packs.
The car drives ok at the moment but it will probably get worse.
I cant think what else would cause it?
Cheers for the replies

 

I'd say maybe you're gapped wrong.

 

Did you replace the spark plugs with the ones with the part number that ends in 6 and not the ones that end in 5?

It's pretty labor intensive to do the plugs. I would recommend replacing the coilpacks too, since you have 40k+ miles on them anyways. Its ~40 per coil-pack.

 

I've had this happen a few times *(twice actually) this year with mine and I'm not sure it's not the "winter mix" fuel we use here in the USA. I had plugs put in last spring, but went ahead and cleared everythign and cleaned the air filter. Kevin has my controller detuning the car right now, so I'll see if that helps as well.

Mike

 

Get those Beru crap plugs out of there and replace all your coilpacks. I had the exact same problem at 45K miles. Coilpacks on these cars dont last that long due to there location (heat) and also age.

 

I paid lots of money for a Porsche Center to do a service and assumed they would check the gaps and make sure they are the right ones. Doh!

Shopping list:
1. 6 x Bosch Spark plugs FR6LDC
2. 6 x 997 Turbo coil packs

 

Also, what should the gap be on the Bosch plugs ?

 

If these are iridium plugs, I wouldn't think of touching the gap.
Mike

 

+1

BTW> I just don't see all the coilpacks and spark plugs failing at the same time. My car has 50K and I'm not sure what has been changed and whatnot and when, but I monitored my car for an hour drive today and not one missfire. Sounds like something that has to do with ignition IMO.

 

coil packs..

 

I had a few misfires too with only 13000 miles on the clock. I had cracks in four of my six coil packs.

 

Were those cracks in the coil or in the sockets?

Call me cheap, but althou the sockets come with coils they can be obtained seperatelly, and they are simply like ignition wires.