Just had the 30k service completed and the car ran great before the service. Now after service it hesitates and does not accelerate well when getting on it. It runs smooth under normal conditions but definitely does not get full power and hesitates under harder acceleration. It does not seem to get full boost either but there is no back-firing or symptom exhibited.

Any thoughts would be greatly appreciated

 

My first thought is take it back and have them fix it Did they do the spark plugs?

 

It's going back today and they did do the spark plugs. Thanks.

I was fishing to see if anyone else has had a similar issue or has a thought as to what could cause this since it did not exhibit this issue before the service. The 30k service is the spark plugs, brake flush, oil/filter change, air filter (not on mine since I have a 8 month old/2k miles EVOMS CAI), cabin air filter, fluids check, etc.

 

I had this problem recently and at 55,000 miles. We located the culprit to be the diverter valves...both were not holding pressure and it got worse as the engine got warmer. Porsche technician said I can install the same ones porsche uses but I opted to go with AWE diverter valves. This has fixed the problem and I have no seen any power loss or hesitation since.
Hope this help and keep us poster!

 

My guess would be the ignition coils, as i had the same symptoms before.

 

Yeah...I'm thinking the coils too...there's a number of things that usually can happen when the plugs are changed. They can overtighten and crack one of the coils, they can fail to put the cap tight enough on the plug, or they can have a loose plug in there that wasn't properly torqued down. One thing is for certain....I do NOT believe in coincidence...and the fact it just went in for the probably ultra-expensive $1300-1500 major service and it comes back to you in worse condition than when it went in leads me to believe they owe you....

 

The shop is a good one and one that I trust with my P-cars but I too thought of similar things... We checked codes and found nothing and they went over the car to see if anything was wrong and could not find anything. They are replacing the new OEM version plugs (Beru) with Denso's tomorrow and will check the coils packs since it's likely electrical in nature as it did not do this before the 30k service. The interesting thing is that if the coil packs were bad then it seems it would send a code and exhibit idle problems. The car only has the issue under acceleration and only gets .6 bar boost when it should be getting .9-1.0 bar.

BTW, my car has the GIAC DME, EVOMS DV's, and EVOMS CAI all of which are about 1 year old (<3k miles) and the car has run fine up to the spark plug change.

 

If they're standing behind their work and making it right for you, then thats about all you can ask....other than the fact it's terribly inconvenient and you're back and forth over something that wasn't done right.

 

OP, do you hear a "honking" under acceleration? If so, that would indicate the diverters..

 

FYI to all on the DV's and honking: I thougt I had that issue on my Cayenne Turbo also and after all was done it turned out to be the intake plenum which as leaking under the pressure from the turbo's. I replaced the DV's with EVOMS thinking that was the issue but it wasn't. The HONKING, if it's DV's, will be AFTER you let off the gas since the extra pressure from the turbo's needs to be released. If you hear noise resemebling honking or a buzz under accleration the problem is NOT the DV's. It will be on the pressure side of the turbo loop.

And thanks to all those who have reponded with ideas. Keep them coming!

 

Let's step back a little, have you tried disconnecting the battery? For like 30 min, and then reconnect.

 

What are the chances they reflashed over the GIAC flash "by accident"?

 

They have not reflashed and they did to a "reset" which did not work. They found small cracks in a few coil packs. IF these were there before the car did not drive poorly like it does now so I'm guessing they did the damage. The car has 29k miles and is a garage queen and pampered. They are replacing the coil packs with the Denso plugs and all I have to pay is the coil packs at $60 each. Does that seem reasonable?

 

A few small cracks in the coil packs? No, I don't think having you pay for the new ones is reasonable since they obviously did it - or did something to make it worse since you had NO symptoms prior to having the work done.

I'd ask what their theory is on why you are having a problem and what their theory is on why all of the sudden your car isn't working right.

Put the ball in their court - - my car was fine when I brought it in, I paid for preventative maint. at your shop and now my car isn't fine - - what do THEY think is reasonable?

I wouldn't pay for new coil packs out of my pocket.

 

I say just get it over with (pay them) and be happy, just IMO.