what grade of gasoline to use - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

jacmed · 07-20-2005, 09:54

I have a 1995 Grand Marquis which I purchase new. I know that the owners manual states that you should use regular gasoline, however, I have always used premium unleaded. With the high price of gasoline now I wonder if I could revert to regular without any problems. My Grand Marquis has 130,000 miles.

BlueSteel · 07-20-2005, 15:10

You should be able to go back to regular. The only prob is you may have damaged your engine, I'm not sure, the car is set up for 87 oct, 92 pushes it if your not set up for it. I think 92 is offered for people that have big trucks or high performance cars that need a bigger ping rate then stock. I run 89 oct due too a modded motor, stamped rockers, msd, bosch plugs, headers, glasspacks, hei distrubitor, and cold air intake with ported intake. I may even be pushing with 89 oct due to stock old rings and pistons.

ryoder · 07-20-2005, 16:53

You shouldn't have any trouble. It might ping little but the computer should adjust it.

BigJon · 07-20-2005, 20:26

using a higher grade of gasoline than your car requires creates carbon deposits. reverting to 87 is highly recommended, asap. do not go to 89.

if you experience some mild pinging (marble in a can sound), you will have to run some seafoam, or chevron w/ techron.