im having almost exactly the same problem and have tried almost exactly the same things.

 

Naw I got it lol. anyways I dont really tune timing on the street you need a dyno for that. I dont tune timing for "how much timing can I ram in there before she knocks" you gotta tune for best TQ at a given load/rpm before the power increase is nill compared to how much timing your putting at it. Anyway the issue is still not fixed. And the weathers been really bad. Im going to go down to stock heat range plugs again BR7ES and gap them to .20 and see what happens.(again)

 

PRoblem fixed!! Kinda... Well I put a set of BR7ES in it gapped to .20 and put in my stock coilpacks (old ones) and no more breaking up issue. ALl the way up to 23 psi shes perfect however theres a little stutter sometimes in 3rd gear but thats more then likely the tune. So I put the BR8es back in and gapped to .20 but she breaks up. So with stock heat range plugs shes fine. Can someone please care to explain that to me? I honestly do not want to run the 7's hitting this type of load ANy suggestions on why the car breaks up only with the step colder plugs?

 

Bump, having the same problem. All ready tryed everything listed to try in this thread. Except the ngk 7's, im running 8's.

 

Just curious, the ones with the misfiring, are you guys running catch cans?

 

Yes, to me...After gapped the plugs to 0.20 everything fine now...