[jbl99]

I have a 97 Deville with a Northstar. Someone told me I could change to a different spark plug (can't remember what it was) and I could use regular unleaded gas. Is this true? Thanks

 

[Submariner409]

Your car was supplied with the GM plug sourced from DENSO which is now known as ACDelco Professional Platinum #41-950. It's all you need, 87 or aviation 110/120 gasoline.

Whatever your owner's manual calls for is the fuel you should run for maximum efficiency, BUT the Northstar uses a knock sensor to detect fuel/mixture problems, so you can run 87 with a loss of a tad of performance.