Detonation ping

[Rednek13x]

Thanks for the reply! That's another thing I forgot to add! When I was running the 87 it would almost always "diesel" when I would turn the ignition off. With the 91 it doesn't do that. I will look over all the vacuum lines and devises that are hooked up. Last I checked the heater valve on the manifold was indeed working as should but I'll check again. I'll check plugs. Thanks again

[68longhorn]

I bought my 86 with 305/700r4 in 2008 at 105k, it currently has 197k and has always pinged for me. I ran 91 when i lived in MD and that helped but not perfect. Timing is 8degrees because less than that I have no power. Since moving to Florida i started running rec89 which is ethanol free and the pinging has gotten much better.

What is the ethanol content where you are? In MD we had 15 percent. Ethanol is a real problem for older vehicles