I have a 1988 trans am. the engine is a 305 tbi. Everything is stock on the vehicle with the exception of the air filter which is a k/n. I am a maintanance minded person and have replaced a great many parts under the hood over the years. I had a friend that worked in the parts business and got most thing rather cheap. The car has always ran strong and without any problems. Recently the car has developed a chatter or perhaps a pinging at low speed acceleration. Once the car is up to speed the pinging is much less when I lay the gas. What could possibly causing this so i could check the vehicle. The last time i looked at the cap, rotor, plugs, wires, or checked the timing they looked ok. thats not to say that I didnt overlook something. Any info. / advice on the possible causes would be greatly appreciated.
THANK YOU

 

Try using a higher octane gasoline. See if that helps. I have the same problem in my '87 Trans Am with a 305 TPI. It pings pretty bad during acceleration.

It probably does it less at highway speed because if you are already up to speed you require less power from the engine to go a little faster than if you are going slow. That is just a guess but it makes sense to me. It's a physics thing about momentum and acceleration and stuff like that, I think.

 

Have the Electronic Spark Timing (EST) module checked out. The module controls the timing of the motor while it's running, if it has gone bad it could be causing the timing to be advanced too far causing your pinging.