Hi All,

Hoping you can help me out. I drove 2002 996TT this morning and getting on freeway it was fine, then about 2 minutes later car started lunging and losing power, almost like the fuel was cutting out. I could barely make it to shop as car didn't even have the power to stay at speed. Every time I stepped on gas could hear huge WHOOSH noise and car would sputter and cut out. I figured that a boost hose came undone.

Well about 5 minutes later getting off the exit to the shop and the car just shuts itself off. I coast to the light, start it back up and limp the last half mile to the shop.

They check codes and see that it's firing an O2 sensor code, and that it detected misfires in cylinders 4,5, and 6. No boost leaks at all, all hoses still hooked up. They start it up, can't replicate what it did to me.

Would the O2 sensor going out cause it to enter limp mode?
Could the O2 sensor start working again thereby letting car run like normal again?
If it's in limp mode, will the car open the wastegates? I can't explain the whooshing noise since no hoses were off.
Could they clear codes, and have car run normally again if O2 was working?

 

Wastegates are controlled by boost, they cannot be opened up to bypass without pressure. Almost sounds to me like a bypass valve got hung up?

 

Thanks! That would cause the whooshing sound I'm guessing? What about the misfires and car in limp mode?