[ModifiedPONPON]

Just picked up 94 formula LT1 today. Showed it off to all my friends first of all. Burned em through first chirped sec (auto tranny). Ran fine and pulled hard all day. Finally showed it to my dad after dark and went to show him the performance and car suddenly studders at 5k and shifts to second and pulls hard and studdered at 5k again? It has 107k miles and not sure of car's history. I have a 10 sec drag car and a 73 formula that i've wrenched on quite a bit. Just not to familiar with fuel injection yet. Where would be the most likely place to start looking for the problem? thanks mike

[David Holmberg]

Check for codes, and I'd bet it's the Optispark starting to go out.

If you don't have a scan tool, any Autozone type of store will read it for you.

Good luck.

[MY1967gto]

Sounds like a miss to me also. 100k miles, could need a tune up.

[quicksilver97ta]

Another vote for the opti. The rotors just cant handle anything beyond the 5200 rpm redline. They use tiny, tiny little screws to secure the rotor. Also the rotors contact metal is held very insecurely with plastic melted rivets. I've had mine come apart at 5K miles revving over 6K. Also, they are very susceptible to moisture in case you cleaned your new engine compartment.

They are fun to swap too, sandwiched between the block and the waterpump. On a new used LT1 car that would be the replaced asap for piece of mind. Get a stock replacement vented unit and get an MSD cap and rotor kit. Locktite the rotor screws down.