My 99 SS starts to ping when i step on the throttle (just slight throttle about 1/4 not stomping it)Cruising at around 1500 rpm's and with the a/c on it much worse!I was thinking the timming might be off but i don't think so any ideas thanks!I run 93 octane all the time!

 

computer adjusts the timing. probly should have it scanned for codes. could be a bad knock sensor. i think a lean condition will do it to. scan should tell more on were to look.

 

Thanks i will take it to autozone for the free scan and see if anything shows up!

 

defo running lean by the sounds or timing is off,

when the air con comes in the timing is suppose to retard I think to help with the extra load, but as it gets worse then the timing is not changing? Has it been re-mapped???

 

The timing is no longer affected by the AC being on or off. That was an old cludge when computers were first used. The load is handled by the idle control system, when the AC goes on, more throttle is applied to keep idle speed steady. Check that the KS is working properly, the plugs are of the proper heat range. The timing is controlled by the PCM in response to engine load, speed, and KS input, unless, as was mentioned before the computer programming was "adjusted".

 

I had it scanned today and its not throwing any codes.Another thing it only starts to ping when the car gets up to operating temp.EGR maybe?Anyway i was thinking of doing a complete tuneup i have only had the car over a month and a half maybe the plugs have never been changed.Hopefully that clears it up.

 

What kinds of tuning has been done to the car? Because that pinging could be pre-ignition or detonation. Pinging is an interesting way to describe it. Pull at least an easy plug to reach and read it just to be safe!