Lot the mods know if this rates a sticky....

May of us have struggled with misfires. I will attempt to explain why they happen and how each component may cause the problem.

A misfire is the result of the spark not being ignited. The reasons for this vary but lets look at some things that make the job of the spark harder.

Lean mixtures.... A lean mixture is harder to ignite than a richer one (within reason). This is why a bad MAF that runs lean will cause misfires.

Cylinder pressure... The more fuel and air that is packed into a cylinder the harder it is for the voltage from the coil to jump the spark plug gap. The mixture in the cylinder acts as a resitor to the spark. More boost and fuel = greater restance to the spark. High voltage will always follow the path of least restance to ground. If your plug wires or cap and rotor are old and cracked then that is the way the voltage will go. If you plugs are worn the gap gets wider and rounded. This makes it more difficult for the voltage to jump the gap and it finds an easier path to ground.

If your car misfires under WOT full boost between 3,500-4,500 RPMS I would first supect the spark plugs. Since factory plugs are impossable to gap I like the denso IK22's. Set the plug gap at 26 thou if you are running stock boost levels and 22 thou if you are running 1-1.3 bar. I can't stress enough of how important it is to have the plug gap be EXACT!!! If you are not the one changing them set the gap them for the mechanic before giving them the plugs. Take your time and don't use one of those round sloppy dial thingys. I like the wire style.

I hope this helps since I have seen may posts releated to the subject with no definate answers.

Tom