jimq

my 03 TT has 68K on it and zero problems with the coil packs at least from what I can tell.

Macster

And I have no intention of challenging that.

All I can do is either post my advice based on my experiences or simply say ask Kevin.

I would hope these cars don't need coil packs, diverter valves, MAFs, plugs, etc. more frequently cause my purchase of a 996 Turbo was based -- in part -- on this not being the case. I hope I'm not wrong or missed something in my research.

I'm not going to throw hardware at the car every time it gets a case of indigestion. This was has not proved to be necessary with my Boxster and I expect the Turbo to perform similarly in this regard.

If it proves to be necessary to replace these items, any items at a higher frequency than what I believe reasonable, then I will do this. Once. Then I wil sell or trade in the Turbo and buy and drive something else, something else that doesn't need this frequent parts replacement.

Sincerely,

Macster.
Sincerely,

Macster.

Receiver

Thanks to everyone for your comments.

I had previously spoken to my own tech who confirms Adam's comments that minor misfires may not throw out a CEL but may get worse eventually throwing out a code. At this point, the only thing I'm sure of is that the plugs are old and need to be replaced. Given the low mileage on this car and it''s age, I suspect that the plugs are just plain dirty. RE the coils, they are relatively cheap given the additional expense of taking the car apart ( bumper, turbos etc ) a 2nd time if changing the plugs doesn't fix the problem. I'd be surprised if the MAf needs to be replaced but this does not require major labour costs to do, so it could be done later if the problem still exists.

I will probably get my tech to drive the car the next time I'm in his area to see what he thinks.

As an aside, the problem appears to be subsiding as I get some aggressive miles on her. These cars were not designed to be garage queens. Notwithstanding, the plugs still need to be replaced and I will likely do that after my tech drives her.

Receiver

Had my Tech drive her. He agrees that she is missing and is pretty sure that it is the plugs. His opinion is it is possible that the plugs will clean themselves with more mileage but that the more likely case is that they'll get worse until they finally throw off a code. We checked and there are no codes yet. I'm having the plugs changed next week. I also have new coilpacks available and my Tech will check to see if there are any cracks in the old ones. If not I'll hold onto the coilpacks for later.

whiteturbo

Replace the coils and don't look back. The labor will be the same while you have it apart. I have six old coils that i replaced at 2,495 miles that were good and still would not consider installing them on another car. It's a long story why i replaced mine at such low miles but 3 months at dealer they found a bad port on a injector after replacing many things. Look at Kevins post he always says replace them.

adam_

How much will your tech charge you to replace the coil packs if the miss is still there when he reassembles? How about if they come back in 5k miles?

If you are DIY, fine- hold off, it's only a few hrs screwing around in the garage...but if you are paying $500, it is nuts to DELAY a $280 expense for 3 months, 6 months or a year- which will cost $500 more to delay.

Just MHO...good luck

A

Receiver

Very good advice from boith of you and of course Kevin. Since I have them, it's dumb not to put them in

JeremyS

It it always a mometary stutter approximately 2 seconds after lifting? I've been fighting the same thing for some time. I can replicate it all day long: Accelerate lightly...lift off throttle a bit but keep it open enough to maintain speed...wait about 1.5-2 seconds...hickup. It's like the car loses power for a split second. I've been told that the variocam can sometimes be felt making the lift changeover, but this seems extreme to me.

I've replaced plugs/coils. Durametric shows normal MAF readings. Lambda does go extremely lean for a split second, and at the same time RPM and Injector time jump up and down. It is much more pronounced at lower RPMs. See attached log images. The first is at 3k+ RPM and the second is a bit over 2k. The second illustrates the wild RPM fluctuations at lower RPM.

Does you car have a tune and/or bigger injectors? Mine does, and I've had a theory that it's a timer on acceleration enrichment of some sort because it always happens shortly after the 'accelerate and lift' sequence described above, and I frequently see the short term fuel trim go to 0 when the stutter happens. Changing the injector size or fuel pressure would surely require some retuning of enrichments, but I have no direct knowledge of the strategy employed by the bosch DME.

Jeremy

Kevin

I need more values to see what is going on. Have you replaced your MAF? New in box vs cleaning.

Is your ECU tuned?

Receiver

Replaced the plugs, coil packs and the MAF. Problem appears to have gone away to be replaced by a very noisy power steering pump. Ah well, it wouldn't be interesting without issues.