Welcome to the not-so-wonderful world of "limp mode". Your ECU has detected a problem and pulled the boost so as not to damage or destroy your motor. Until you scan the diagnostic trouble codes (DTC's) stored in the ECU, it's very difficult to speculate on a cause. There's a fairly good chance the problem lies in the air/fuel mixture, i.e. the motor is/was running lean so protective action was taken. A lean AF mixture can be caused by lots of things; a loose hose or air leak, a diverter valve going bad, a bad MAF or something that was temperature induced. There's also a chance that it could be something completely different. When you restart the car, everything resets to normal and if the problem is transitory, life will go on as usual. But if there's a real issue, it will eventually return to limp mode, sometimes accompanied with a CEL, sometimes not. At best it's a quick fix and temporary pita but at worst, it can be a very difficult diagnosis to make and remediate. You may want to read the "air leak" thread as a couple of us have been dealing with similar issues for a number of months now. Good luck!

 

Steamboat is exactly right.

 

Thanks for the input gentlemen, especially buzzm (lol). Steamboat, I feel you hit the nail right on the head because I have noticed the inside of my stock exhaust tips are white in color instead black (like when I had the stock exhaust) indicating maybe running a lean condition. But would the car run lean just by adding an aftermarket exhaust and nothing else? shouldn't the stock ECU adapt on its own? (if there isn't anything else wrong with the car) Just some thoughts. I will get it looked at and let ya guys know the conclusion.

 

I had a similar issue which eventually got to the point of no boost every time I drove it. In my case it was the connector to the boost pressure sensor on the Y Pipe. The cable is way to short and is probably the most disconnected and reconnected plug on the entire car. No real surprise it failed. It displayed itself as an overboost error in the end. Easy to check. When the car is idling jiggle the connector and listen for a change in the idle.
Worth a look.

 

Thanks Meister I will check that.

 

My bet is that somethings wrong with the o2 sensors. Something must've gone wrong when you had the exhaust changed. Might be broken, not fastened or maybe put in the wrong order. Good luck

 

With mine the throttle body boot came loose while on the track - no boost but had power to drive it. When I push the throttle the turbos would whine and no boost. Put the boot back on and back to normal. Only happened after being on the track for some time when the car heats up. I had the Fabspeed cone-cold air intakes and AWE cat back exhaust.

Sounds like you might have a leak somewhere.

 

Yes it cant go lean if the o2 sensors are on the fritz or if they tell them motor there is too much fuel based on the new exhaust flow. The ECU will lean it to fix that "supposed" condition.
I melted cats in a different car messing with o2 sensors, then blew the motor due to lean conditions on the same car. While most people dont think an exhaust can do that, the o2 sensors do tell the ECU what is going past them so the ECU can adjust.

 

I had a very similar problem. The independent shop that I use solved the problem by lubing the turbo actuators with a silicone lubricant. It has now been three months and no recurrence.

 

Well ladies and gentlemen I took it to the dealership shortly after this post and haven't commented yet after the fix so that I could put some miles on it and ensure the repair was indeed a success, in which it was. As I mentioned in my original post that there was no illumination of the check engine light when it was exhibiting the 0 boost condition so I figured I would get the good old "cannot duplicate symptom" from the dealership however that wasn't the case. The vehicle was scanned with no codes found. After some diagnostics by the Porsche technician the following was found, repaired and I have put approximately 500 miles on the beast with no issues. The malfunction and repair is as follows: Bank 2 turbo charger vein adjuster does not move freely. Tried to free up with penetrating oil and special lube. Adjust will not move freely. Ordered a new turbo and replaced same. Road tested vehicle and checked for faults. The service writer informed me that they have been seeing this type of issue more frequently lately. Hope this helps anyone who experiences the same type symptoms. Also, Thank You CPO, you saved me approximately 5K...lol