Question: Is this Knocking ?

[gmhowe]

When driving if I punch it, for a few seconds counds like someone is rattling a can with a bunch of nuts in it. it goes away, just curious what it is and can it be cured.
Thanx
Gordon
96 CE LT1

 

[killain]

Sounds very much like octane pinging, like marbles in a soup can, and it deminishes as you let off the throttle. If you punch it at say 40 MPH and it starts the pinging again then it's octane knocking. I would assume that your 'Knock sensor' is not working anymore. You have an LT1 engine and it should set a code if the knock sensor is out of commission. I'd have a shop check the ECM to see if any codes have been set. I'm not sure of your perticular owners manual, but it should tell you what octane gasoline your engine takes. good luck.

 

[gmhowe]

It states to use Premium which here in Phoenix is 91 octane and which is what I use. Will check out the codes this weekend haven't seen any SES light on since I bought it.
Thanx
Gordon

 

[killain]

could just be a knock sensor !

 

[mdsbch]

I had a similar problem. When it was under load at around 2500 to 3000 rpm it would start ping (knocking) and go away as the rpms came back down. It turned out to be the #2 exhaust lobe was worn down. I was told there was a problem with soft cams in the early to mid 80's. I replaced the cam and the problem is gone. The lobe was almost completely round. A way you can check it is remove the valve covers and spark plug wires or coil wire so it wont start. Then have some one crank the engine a few times. Watch the rocker arms and valves to make sure they are all moving up and down the same amount. If any are not, it could be a worn lobe or a bad lifter. Good luck.

Mike

 

[tonylong]

My 89 L98 is happy only with 93 octane, it loves 100 (Shell Super Premium - not locally available). I've found Shell to be consistently better than the others.