the other day with my radio turned down i herd a sound that sounded like the car was pinging i was cruising around 45mph and went back on the accelerator when it did it so i came off the accelerator and the noise went away then it did it again a few more lights down the road. i took it into the dealer and they said the typical what type of gas am i using and i said premium like the car requires always use it. no codes were found. the Tech called GM and was told to run two full tanks of premium thru the car and see if problem went away. well it hasn't and the tech hasn't a clue what it might be. anyone else experiencing anything like this. read online about Detonation but not sure if this is something that is always there or comes and goes like my problem. the sound is like someone banging on metal really fast. ive checked under the car for anything loose and haven't found anything. just so you know it only doesn't when under load ive tried to get it to do it while car is in park and nothing car sounds fine.

 

Sure sounds like knock to me...what mods are done to car? Tune?

 

bone stock , only have a stock replacement K&N in the air intake. any suggestions , i purchased the car about 3 months ago its always done it.

 

With the K&N air intake, the fuel trims might be adding fuel in closed loop or cruise to compensate for the additional air. Unfortunately, this added fuel carries over to open loop, WOT. That causes more fuel in an already rich condition. That can cause carbon build up or even detonation.

How many miles on the car? How is the oil consumption?

You might want the service tech de-carb the engine. This removes carbon build up on the pistons and rings. The best method is removing the plugs and injecting a de-carb chemical in each cylinder. The car sits for a few hours allowing the chemical to dissolve carbon build up on the piston and ring lands. Then, the chemical is sucked out, plugs installed and car driven to burn off excess. The other method for removal of carbon build up is using a vacuum source to suck a chemical in through the intake slowly, not to cause hydrolock, and let car sit for an hour, then start up to burn off excess.

Also, when they remove the plugs, using a scope, they can see how much carbon build up is on the pistons.

If it is carbon build up due to an overly rich condition, a tune will fix that.

If it is carbon build up due to oil consumption thru the PCV, a catch can might help.

Or a combination of both!

 

Mike the car has 29500 miles on it currently. Ive got an appointment for next tuesday to go see the guy that tuned my old 2002 Vette hopefully it isnt something to serious thanks for the advise im gonna have him do the carbon cleaning also.