Originally Posted by
APGSpyder
Is there a better way to mount the engine other than directly to the firewall? Like use a soft mount???
Use "well nuts" in lieu of "T" nuts at the firewall. Adjust for the proper resilance & use " nyloc" nuts on the back side to lock the adjustment.

Given the set-up you describe, I would suspect a bad ground on the plug lead. Maybe a lose cap or a bad ground at the module.