Basswacker

I have a 1991 302. It pings when I use regular gas when I use premium it doesn't ping. Coil distributor plugs wires have all been replaced recently. It was pinging before and after I changed all that. Engine temp is fine(going by gauge) and radiator is always topped off. I did the seafoam through the brake booster line to try to get rid of any carbon and that didn't change anything. I'm sick of running premium I want to save some money and solve this problem.

Thanks

justintendo

need to check ignition timing, verify its not too advanced

jayber

yup set it to 10*

sdmartin65

Try using regular gas from some different stations and or brands.

Replace the knock sensor, it won't throw a code if it is functioning even at a minimal level. It has to go completely dead before it will give a cel.

Sounds like one of these areas is the problem, most likely the knock sensor.

1988 F150 Custom

Block off the EGR passages (I cut a "plate" from a soda can) and see if the problem goes away. If your EGR valve is sticking partially open you will get pinging under load, ask me how I know LOL. It creates a vacuum leak and runs the motor too lean. My 88 decided to do it when i was towing a boat from Tennessee to Illinois. I tried backing the timing off and it would quit pinging but the timing was so far retarded that it ran like crap. Made a block off plate at a service station in KY and has been fine ever since. If it doesn't fix your pinging, you can simply remove the plate between the EGR valve and the intake.