So I have read through a lot of the other P0101 threads and have not seen anything with a similar issue as I am having. The code will set, car will go into limp mode with only mechanical boost, and, when I clear the code, the car will make between 19-21psi until I shut the car off yet again and restart it. Car is a 2009 SSTC Sedan with K&N SRI, Forge BPV, ZZP catted downpipe, and is NOT tuned. Have checked the two service bulletins that GM has out for it with the wastegate actuator valve nipple being damaged and the radiator support bracket bolt punching a hole in the cold side rubber coupler, of which neither is an issue. Had a spare MAF so I swapped that, still having the issue. Any help would be appreciated, especially if anyone has had the same over boosting issue after clearing it.

 

I'd bet it's a boost leak. Build a boost leak tester and start there, could be the condensation bar on the underside of the intercooler. Enough air leak to set the code but not enough to cause a serious drop in boost levels

 

I have same problem exactly. Mine is 08 sstc stock with k&n typhoon. Did boost leak test and held pressure. What did you find out?

 

I have same problem exactly. Mine is 08 sstc stock with k&n typhoon. Did boost leak test and held pressure. What did you find out?