I have a 98 Z28 and have recently changed the plugs and plug wires. I now have a misfire. Put it on a code reader and it said it was #7 that was the misfire. I changed the plug wire and still had it. I then changed the ignition coil pack and still have it. Any ideas what it could be? It doesn't do it when the car is first started. It only does it after the car has been running for a couple of minutes.

 

try a new plug. sometimes all you have to do is drop them and toast. what plugs you using?

 

also double triple check your plug wire order to make sure they go to the right cylinders.

 

Im using AC Delco Rapidfire plugs