Studdering under boost

[mbagge01]

I have a 2004 cayenne turbo with evom tune, newest revision coils, spark plugs, fuel pumps and filters which acts strangly when warmed up. When car is cold, it drives great and pulls hard under WOT. Once engine is warmed up, the car drives fine under mild and moderate acceleration but under WOT, my aftermarket boost gauge reports that pressure build up to expected 14-16 psi range but the vehicle either starts shuddering under boost and feels like there is no power when accelerating. On rare occasion it goes into limp mode but after about a minute is fine. I have checked durametric multiple times and there are no codes. My suspicion is something electric is going on when the car heats up. Solenoids maybe?

[lewisweller]

Did you ever fix this? I have a ctt with E81 power kit from new as option from dealer, my boost is +0.8bar but I also have he shudder stutter at 2000, 3000 and 4000rpm approx and yes when boosting.

I have researched the n75 solenoid which controls the waste gate is to blame. It is located next the Throttle body, it has three vacuum tubes and one electrical connector attached to it.

Another possibility is the map sensor, try removing and cleaning it and lastly the maf sensors cleaning.

I've found with mine if driven for some km like 1000 the problem will lessen but not disappear, when I disconnected the battery and reconnected it ran rough for ages. Dme learning? Or dme update required to address? All questions and no firm answers so far.