Failed ignition coil

[GaryD]

Re: My July 2003 996 C4S, 6-speed (manual)...

I posted a while back about an engine 'blip' that I occasionally noticed in the 1500-2000rpm range, especially when the car was re-started from warm.

Well, in December the car 'failed'. After pulling away from a junction with some unusually spirited use of the accellerator (but still under 5-6K rpm as in the manual, since I was running in) I drove the car about a mile or two (sedately, and without problems) and parked up. On re-starting the dash lit up like a Christmas Tree (topical) and the computer told me to drive to the workshop. The car sounded like a tractor (missing heavily) and vibrated like mad.

So, Porsche GB put the car on a truck and returned it to the dealer who, after a few days' playing with the car, told me that it was a 'stuck hydraulic valve' and returned it to me.

Well, I was hopeful but on driving the car again it was obvious that the problem hadn't been fully fixed, even though the warning lights were not on now the car occasionally 'vibrated' or 'missed' in the 1500-2000rpm range. I complained to Porsche GB again, but the car seemed to rectify the fault on it's own and I didn't have a problem again so I forgot about it.

Until last weekend.

Again, same scenario. Pulled away from a junction in a sprited manner (but still in under 5K-ish rpm - i.e. not floored), and then drove home sedately. Re-started the car and... you guessed it, Christmas tree lights and tractor sounds again!

So, the car has gone back to the dealer (different one this time, as I lost faith in the old one for many reasons) and they have diagnosed a faulty 'ignition coil' (?) and replaced it.

They claim it is now OK... but given the above (and my reluctance to return the car a third time for the same fault) does this sound plausible? I guess I am now a little paranoid about the whole thing, especially since the car is just 6 months old and has 1500 miles on the clock (weekend car).

Any comments and/or advice would be welcome.

Thanks again,

Gary D.

Edited February 11, 2004 by GaryD

[Tool Pants]

I do not know what was wrong with your car. But the coils, like anything electrical, can go bad all of a sudden. Each spark plug has it's own coil on top of the plug - there are no spark plug wires or a distributor.

When I replace plugs I check the condition of the coils and they have been know to crack which will cause a misfire. Jeff