From what I have heard the engine ignites better with the 87 octane and people don't see the need to use premium except in a case where there maybe a problem with the fuel. Sounds like your son might of got that gas that is near the waterline when the tanks are low in that case yeah use the premium for 1-2 tanks then go back to regular it should be fine. I will use 87 as I don't see the need to throw away any other $$. I hope this helps
