Helllo guys, I've got a 1991 Z28 that just doesn't seem to run right, I was wondering if there was an updated prom or something from the factory. EVERYTHING IS BRAND NEW the timing is bang on at 6* base, headers, full exhaust 2500 stall, and 3.73 gears on my LB9. It runs great when its cold, and there is tons of power but when it gets hot it doesn't pull anywhere near what it should. And it seems like the converter wants to lock up even in first. Any help would be greatly appreciated. thanks.

 

Welcome Aboard!

AFAIK, here were no "updates" to the later programs from the factory. Earlier year TPIs had some revisions from the factory after the end of the model year to resolve some problems, but later models came with the final revision.

With a change to a better flowing exhaust, steeper gearing, and a loose converter, the efficiency of the engine has probably changed somewhat. That may require a bit of adjustment to the stock programming for best results.

As for the TCC, it can lockup in any gear, but the conditions required to allow lockup usually don't occur in first gear, unless you're holding it there manually.