I have taken off the throttle body and cleaned it. also no carbon in the intake. Have changed the inline fuel filter, also taken the gas regulator apart and cleaned it along with changing out the lockout solenoid which just recently went out. Vacuum is good off of the vacuum advance. Even went as far as changing out the ecm, I'm at a loss.. The only thing not changed out at this point is I assume its a throttle position sensor on the front of the throttle body but I would also assume it would either be working or not like most toyota parts. Its the spike in acceleration once in a while without warning and there are times it dies while sitting. I just adjusted up the amount of fuel coming in from the regulator and also adjusted the idle up. The test will continue tomorrow with hopes that it takes care of the problem.

Yes and when your peaking down there look for carbon! You did change the LPG gas filter? It's in line, right after tank. Not always listed by toyota, mostly with "piping". Is the vacuum advance working good? engine slows down with it unhooked at high RPM?

Inspect the throttle body and clean as needed. Sounds like it's having trouble breathing with the butterfly coming to rest. It's having to work to maintain an idle.