My 85 GSL-SE has developed a high rpm stumble. As I accellerate and get near redline, the engine misses and stumbles until past redline. It happens between 6-8k rpm and is not a huge miss but definately noticeable. Only happens under load. Revs fine while in neutral. Fuel pump and filter are recently replaced (6 months ago) as well as fuel pressure regulator.
This is on a stock EFI 13B with only mod being Racing Beat roadracing header and exhaust.

Any Ideas?

 

cap -n- rotor good?
ignition wires arcing/arching (sp?)?
timing within spec?
are the injectors clean?
are all six ports opening?

sorry can't think of anything else right now, but by the time you check these things, maybe someone will have some better, more helpful, ideas.

peace

 

Timing / Plugs / Wires / Coils

In that order.