No spark

[Revsracing99]

Alright, started with code 42 that would not clear. It is now cleared. I have changed distributor, module & coil cap & rotor. Now it will start and idle, and as soon as I come off idle it dies and will not refire. It has no spark from the coil. I have no codes. Could knock sensor cause this? If I unplug it will that confirm it is good or bad?

3.4L GM performance
TBi

Mike

[Revsracing99]

Brand new coil was bad, as so as it got hot it would quit. But I still back firing trough the intake under a load. No code. But it does show some flags. I bought a also cable for my lap top. What is best software to use with it?? I'm using winnaldl.
Mike

[geoffinbc]

Backfire indicates bad (retarded) timing be sure to set it correctly before you drive.