My 1991 305 tbi firebird makes a dieseling/knocking sound that sounds like it is comming from the engine. It happens when i press the accelerator but then stops after a little bit. It happens more if i press the accelerator down just a little bit. The sound doesn't happen in neutral or when it is ideling. Thanks the help
-keith

 

Sounds like the typical pre-detonating. Check to see where your timing is at, check to see what it does when your bring up the rpm's also. Parts inside your dis may be going bad casuing the timing to jump around if this just happened all of a sudden out of the blue, but if you;ve been messing with the timing, it's possible you just put too much in it. Stop now before you burn a hole in your piston.

 

Also you could have a rod knock... Does the knocking get faster as you accelerate?

 

That's what I was thinking also. A rod knock isn't usually heard at idle or when held at a steady rpm but only when you rev it up. I've heard lots of rod knocks in diesels.