2004 Pontiac Montana engine ping and knock

[crooks]

Hello everyone,
I have a 2004 Pontiac Montana that has an engine ping and knock since new. I have had the fuel pump changed and the fuel pump module replaced; nothing changed. The fuel injectors were flushed and I have been adding fuel system cleaners. Increasing octane seems to only help a bit. I have noticed that sometimes it takes a few seconds longer to start at times. There is no check engine light coming on. It is more pronounced when accelerating hard and just before it upshifts I will hear a loud rattle and knocking. The dealership says that they can hear it and it was 'normal'. I don't think so. Oh, I almost forgot, they also changed the knock sensor. Please help!!!! It's diving me nuts!!!! Thanks

[geoffinbc]

A bit of ping is considered normal on 87 octane. By the way whos gas are you running? Put in some Chevron 89 and I bet you will see a big change. Keep in mind things like ambient air temperature, engine operating temperature, engine load and gasoline all play a big roll.

[crooks]

I have tried every kind of gas. Petro-Canda, Esso ,sunoco...ect. No change....

[geoffinbc]

Ok well the KS system can only remove so much timing in order to remove pinging. Can the dealer see that the KS circuit is active when it is making the ping?

Just keep forcing the Warrenty claims man.

[Doubt_Incarnate]

if it is still under warranty. if it is, beat it like there is no tommorow and break it, get a new motor for free. wasnt there a recal on some motor gm put out for improper piston-cylinder clearence? to much slap i think it was but i dont recall the motor.

[bszopi]

It was the 3100s for the first few years they were issued. GM has since fixed the issue, so that wouldn't be it.

[RednBlack]

"Ping" is pre-ignition. Never normal. You apparently have tried all the gas available. Your dealer needs a nut-kick also. I agree, push the warranty issue.

[BobbyVenture]

Ya, my venture NEVER does that, its not normal.