Pontiac Grand Am

Hello. Any Advice Would Be Helpful. Lol the title pretty much sums it up. My car pings realy bad. Ive changed the wires, plugs, air fliter, fuel fliter, and I even put in 93 octance gas and it stills pings like a rainstick. I have a 1990 Pontiac Grand Am. 2.5 L approx 170K miles. Maybe thats it. Sound like a head or valve problem or what? Im lost I even bought a new egr valve not to long ago cuz I heard that will cause that. It pings mainly on black gravel roads. Any other road is hardly noticable and when the car is sitting sitting still. It dont tick it just pings
January 21, 2007.

Check the timing, don't forget to ground the diagnostic terminal.
Could also be the timing gear ( I believe this engine uses a gear).
Heavy or constant pinging will cause engine damage.
Pinging occurs under load, almost never at idle and if it occured at idle it would be MUCH worse under load.
Are you sure you don't have a loose heat shield rattling that sounds like pinging.

Jan 26, 2007.
Naw my car doesnt have a heat shield. And on my harmonic balancer is has no timing marks so I dunno how. But its does it pings bad.

Jan 26, 2007.