This post is for my younger brothers 2000 ss that has all bolt ons. Just recently the car has been missing real bad and real sluggish throwing the P0306 code. At part throttle the car just sputters extremely bad and once u give it a bit more gas it quits and and goes back to normal but once its back at part throttle it misses hugely. Scan tool is showing well over 2000 missfires on Cylinder 6. We changed all the plugs tonight and checked all the wires and still Scan tool shows Excessive amoutns of missfires on that cylinder. Valve Train is very quiet so I am hoping its nothing internal. This is a bolt on car only. Could it be an injector? Coil?
Please help. Thanks
Car also has 58K miles.

 

Is it a 6spd car? Ever missed a shift? I would check the Valve springs and pushrods on that cylinder... I had the same problem with mine and it was an exhaust valve spring..