Everyone says Vettes don't ping. Well mine does. Part throttle ONLY. Get to overdrive(4th) doing 30-40MPH and try to accellerate a little bit, ping ping ping. Yes i'm using premium, tried several brands - no diffence. Tried octane booster, the ping laughed. It's a 2000, 24K miles, Automatic. Had it checked out thoroughly. No codes at all. Computer is totally stock; un-touched. I had the injectors/fuel system cleaned out twice @ the Chevy dealer. Had one knock detector replaced since it was "slower" than the other.

One hint.....when I'm in 4th and I "call for power" to go just a bit faster, the engine seems bogged down, pings like mad, but doesn't downshift to 3rd. Seems as if it thinks it's supposed to be in overdrive and doesn't budge. If I hit it much harder, then finally it jumps down to 3rd. I think if it downshifted when I am calling for power, it wouldn't ping - but that's my un-professional opinion.

This is killing my fun. None of my buddies have Vettes that ping, why does mine?

Does it use oil? Oil will decrease resistance to knock. But if it is happening at light load only, I would think it is not a threat to the engine's life.

Was a decarbonization (topend cleaner) procedure done? Or is that the fuel injection service you are referring to the same thing?

Did they road test the car to see if you were getting knock retard when it was encontered? I am wondering if the noise is actually from something loose in the exhaust system that is causing the sound, but the vibration then is picked up by the knock sensors and causes the timing to be pulled and results in the bogging.

The knock sensors getting faulty readings is a good idea. Also the knock sensors may be faulty as well.
Check your spark plugs. They may not be burning all of the fuel.
Check your spark plug wires. They may be keeping your plugs from getting the current they need.
As a final resort if replacing plugs, wires, knock sensors, and new updated ECM code doesn't work, then you could try an alcohol injection system (like the one Halltech sells).

It's probably something simple like plugs or bad knock sensor readings.

Good luck!

Hey guys - thanks for the quick replies. To answer...no it doesn't use a drop of oil. At 24K miles, I didn't think of the plugs...but I'll check/replace. Yes it was a decarbonization (the dealer did this and said it needed it twice. Lots of carbon in there). I can say the engine is running smooth and quiet, except for the pinging. Changing one knock sensor seems to have helped about 50%, in the 30 MPH range. But it is still there. I may not be pro's like you guys, but I know detonation when I hear it. Remember it well from the old days :-))). A friend of mine hooked up an "auto-tap?????" with a laptop. It shows that when I am lightly accelerating from 35MPH or so, trans is in overdrive, the timing drops. At first he thought I might have a bad chain. But after thinking about it, I guess the knock sensor sees the ping, and retards accordingly. At idle, the timing was 13.5 to 14 degrees. Race the engine in 'park' to 2000RPM, it's up to about 38. Don't know if this is within tolerance. The Chevy Sevice manager is going to check it one more time on Tuesday.

Bruce - I miss LI. Been in Dallas 2 years. Big difference.

I have two C-5 Corvettes. 98&99. One with a A4 the other M6. Sunday my wifes Corvette was pinging slightly under small load. Then today mine was pinging under full acceleration. Both days were 90 degrees plus. Neither of them did that before, untill these hot days.

Maybe you should see if a different brand of fuel would help. I remember NY doing a check a number of years ago and discovered that a very significant number of gas stations were selling low octane gas as premium.

I personally had a situation where gas that I had bought in CA was at least 11 mph slower in top speed than gas I bought in Yuma, AZ. That's quite a difference.

Finally - no more ping......this is what fixed it. Besides replacing the rear knock sensor & connector, and a full decarb (twice), the technician at the dealer put the GM2 on the car and we drove. Everything looked perfectly normal. So he took the car in the shop, went into his GM site, (this is basically what he said) plugged in my VIN and searched for Spark Knock. Lo and behold, there was a fix for the computer. The fix covers spark knock, erratic fuel guage, and some other code. He said it wasn't a full "bulletin" but was listed anyway. The car runs perfect. No ping, no bogging down, no "stuck in 4th unless I really hit it". I'm done.

Thanks to all who helped here in the forum.

This is amazing. I just dropped my '99 Vert (19000 miles, auto) off at the dealer this afternoon for the identical problem. In fact, your symptoms are so identical that I printed out this entire thread and will drop it off at the dealer first thing in the morning. Hopefully the tech's will be able to apply the same fix for mine as they did for yours. I'll let you know how it turns out. Thanks!