okay so my car is running rough and the boost gauge on my car is bouncing around 15"-20" of vacuum,the car is popping and banging like its running too rich and the car is shaking really bad at an idle. I already changed all the spark plugs and all the ignition coils. I'm thinking bad piston rings or chipped piston and or pistons. suggestions?? i know the pulley on the supercharger is a 3.4 instead of a 3.8 like it should be and i know i ran the car kinda hard so i know that its my own fault for not doing research before i got the car.