[stlrec]

I have and 03 H2 with a Magna Charger on it. I put 84 oct. in it and the check engine light came on. I called onstar to run a system diagnostic. They would not give me the code , but said it was the engine fuel control system. I then took it up to the neighborhood AutoZone and they said it was p1074 twice which usually means that it is the MAS. Would bad gas or low octane cause this ? I'm Leary to take it back to the dealer since my extended warranty got voided because of the super charger. I had to replace my transmission and was thinking maybe a loose vacuum hose might be causing it.

Thanks for the help.