I have an 02 WRX with 105,000 miles on it and I am constantly getting misfires in all 4 cylinders... can't figure out what's going on. I am running a Cobb AP, SPT intake, and that's really about it before the engine. I thought it might have been plugs, but had those changed and still get the same problem. I'll clear out the CEL's and they come back usually within 24 hours. Any ideas? My car seems to be running fine, so I'm at a total loss at this point.

 

when is the last time you updated your AP online? And then I would check all the grounds on the engine and then the coils them selves.

 

Ya check the coil packs as well

 

Possible vaccum leaks?