[Merl]

No he worked for GM, on cadillacs, dont remember his name. Yes I may be wrong about the knocking thing. It was a while ago that I talked to him. I do not know every thing about cadillacs. And i wasnt sayin over a long period of time on the knocking thing, I ment only for a few thousand miles until your next tune-up then switch to premium. I use medium, and occasionally premium and have never heard knocking, and my granddad used low-grade for 11 years.