Hello Everyone,
I have a 2006 Grand Prix GT with the supercharger. I has been a great find, we bought it with only 51,000 miles on it from a gentleman who took perfect care of it. He had extra money and he threw it at the car. Just prior to us buying the car (May 2012) he replaced the spark plugs, the fuel filter, changed the oil in the supercharger, changed the oil and filter in the transmission, and new brakes, and I have seen all the documentation for it. Only thing we have done since buying it is change the oil and fill it with gas. We are using synthetic oil in it with a K&N oil filter. Now, I say daily driver, but when I say we put miles on a car, we put a LOT of miles on it. The car reads as of today 91,515. I have also put new tires on it. Still, no problems with the car till we drove to Nashville a month ago and the check engine light came on. My friend and I are not mechanics, our wives are in medical school, so we are both broke just waiting for our lottery tickets to mature and be worth some money. We hooked up the car to the scanner and it gave a P0033 code and P0304 code. I put a can of Seafoam in the gas tank and checked for vacuum leaks. I bought a Supercharger Bypass Solenoid from RockAuto.com and cleared the codes and the car ran like a champ again. No problems for a couple days and I drove the car to Mt. Vernon, Illinois and back home (about 800 miles) with no problems. The next morning my wife took the car to school and she said it wasn't running right and the check engine light began flashing. At this point I had no idea what a flashing CEL looked like so I took it for a test drive to diagnose it myself.
If I didn't use the Engine Boost the car gathered speed just fine. We live in East Tennessee so we have a lot of hills and when the car downshifted and the Enging Boost spiked the car immediately began sputtering and the CEL began flashing. I babied the car home and checked all the spark plugs. I am not a mechanic and have never claimed to be, but the plugs all looked the exact same and were gapped the same. Wires look to be original and in good shape. I changed the Air Filter. The CEL initially stayed on and was showing a P0301 code. I read that the Ignition coils may be bad so I switched them around and reset the codes. I drove it around and it does the same thing however just doesn't give me a steady CEL afterwards. Of course I have been searching the internet all day and have found a thousand things to look at. I started with vacuum leaks and did not see any. I checked fuses and for loose wires and didn't see any. I tapped on the catalytic converter with a hammer and it sounded very solid, I didn't notice any rattling. I have never owned a supercharger and just read on another couple forums I shouldn't be running 89 octane fuel in it. We are making that switch starting today. What else should I be looking at? As you can tell we need this car back in running shape as soon as possible. So I will be working on it all weekend. Budget is tight so I can't just throw blind money at it or afford $80/hour labor charges. Any and all help will be appreciated.
Sorry to be so long winded.
Originally Posted by railsplittermedic
