Randomly my service engine soon light comes on and I have it read for multiple misfires. The light comes and goes. I had this issue in my 1999 Camaro as well. I have msd ignition with some decent spark plug wires. Not sure what could be the problem.

 

what codes? mulit misfires are tough to find. start testing sensors. pick up a spark checker and see if you have a weak coil.

 

P0300. That is something I will check. Could having some cheap spark plugs be causing the code because of the msd ignition?

 

cracked plug insulation/ceramic will do it.

 

If ignition checks out OK, look for a lean fuel mixture, as that will cause all cylinders to misfire randomly. Check fuel pressure with engine under load, FPR function (with engine idling disconnect vacuum line to FPR, fuel pressure should go up about 6 PSI), check that EGR is not stuck open, make sure O2 sensors are switching state rapidly, although they usually break an cause a rich condition, clean fuel filter. Mismatched injectors will also cause problems.