Alright I have done some searching on over boosting and I see the most typical problem is a clogged cat. I have had that replaced and am still having a problem.

My car is a 2006 SS/SC Stage 2 with 35k on it. One day I notice the exhaust was sounding pretty raspy and a pretty loud metal vibration under the car on acceleration. Also, now I'm boosting just nearly 20 PSI. Normal max boost has been around 13.5 after I got stage 2. When the car is idle everything seems/sounds normal. Figured something wrong with the exhaust system. So I take it to a couple dealerships, one says new exhaust, the other says new exhaust and cat converter. The second is willing to fix it under warranty so I go with them and they replace the forementioned. Now the vibration seems to be gone and the raspy noise is nearly gone though the exhaust just seems a lot louder than it used to be which I guess I can live with. The main problem that still exists is I'm still boosting nearly 20 PSI even with a new cat and exhaust.

Any ideas?

Also to anyone in the Charlotte, NC area, is there a good place to take these tuner cars in for repairs? The dealerships I have been to haven't given me a lot of confidence. Now my warranty has expired, I am looking for a good repair place that knows how to deal with these tuner cars.

Thanks for the help.

 

I am mostly stock...airbox mod, catless 3in to 2.5 to a SR.S catback..
and I am tuned... on cold days i am seeing 14.