did a search but came up with nothing greatly useful. main thing that baffles me is it only does this SOMETIMES, anyway it started again today (forgot about it until it did it today. its very light misfire but i can tell its running weaker when it does it, seems like those last few hundred rpm last forever before the shift... but it only does it over 5500 and barely noticeable.. doubt ild notice without my exhuast work. figure ill start with changing plugs and wires, and im about to change the fuel filter too. anyhow anyone know whats most likely to cause this? and why it only does it sometimes?

 

You need to search harder, Its a very common problem with the LT1. I don't know if anyone actually "knows" what causes it as there are many different problems with the same symptoms. I think it is generally contributed to the opti-spark though. Could be wrong, just do another search.

 

ok did find a few things by doing a search on the opti instead of high rpm miss... most ppl found it to be the cap/rotor going out on the opti ... great just what i need the night before i decide to go back to the track