i just picked up a '85 el camino with the 305 and the quadrajet 4 barrel. the guy i bought it from said the previous owner rebuilt the carb but didnt hook up the ecm (but its been hooked back up since then. well he said unless you use premium gas the engine will diesel when you shut it off. is there a way to fix this? would i be able to use unleaded with octane boost each time i fill up? any other ideas?