I'll try and find the startup sequence i ihink it was in a post by 8in avee on a forum. But i don't imagine any sensor will be to blame if it starts up perfectly on easy start. Gradually take all the sensors out and see if anything's obviously wrong.ie crank sensors can be affected if the plate is cracked or the signal can be fuzzy if metal gets stuck on the end. Gems is prone because the trigger arrangement is very flimsy bent metal( Thor is cast and machined into the flywheel) .