Originally Posted by
Shrek
It is always helpful to post your tune, when asking such questions.
Speartech (and other wiring harness companies) often sell the Corvette APP (accelerator pedal) for use in LS conversions. This APP is not always compatible with the other components that make up the Electronic Throttle Control system.
Sometimes the ECM tunes will have select Electronic Throttle Control system DTCs disabled, but often after enough drive cycles, the "background" diagnostics (like the second ECM core) will start to shut things down.
This may manifest as a sporadic or intermittent issue, or as a dead pedal, or as a no start.
Until you post your tune, and list your Electronic Throttle Control system components, there is no way to know if this is indeed part of your issue.