\'89 blazer pings on part throttle acceleration Hey all, I'm really liking my newly purchased '89 Blazer. Way better than one of them sissy import SUVs. ;-) But, it has a minor problem. Driving on a flat road at say 60 mph, it'll ping a little when I give just a little more throttle. Hills do the same thing. Down shifting out of OD reduces the ping. Engine has 150k, new plugs and rotor. I'm using 87 octane fuel. Running 31x10.5x15s with 3.43 diff ratio. stock tranny. More throttle stops the pinging. Otherwise runs great! I'm thinking manifold leak of some kind, or carbon deposits. Anyone had something similar or know of a common cause for this problem? Or am I due for a lengthy trouble-shooting session?