Just bought an 05 with 26K on the odometer.

The thing intermittently pinks/knocks alot. Octane of the fuel does'nt seem to affect it much.

The dealer was advised by GM to de-carbonize the combustion chambers and clean the injectors. Have not gotten it back yet to see if that fixes it, but I'm a little skeptical since it does not do it all the time.

Anyone else have this problem?


murf2222

Although i use 98 octane fuel, i can hear similar sounds while on idle only. I haven't had the chance to send it to the dealer yet.

Just bought an 05 with 26K on the odometer.

The thing intermittently pinks/knocks alot. Octane of the fuel does'nt seem to affect it much.

The dealer was advised by GM to de-carbonize the combustion chambers and clean the injectors. Have not gotten it back yet to see if that fixes it, but I'm a little skeptical since it does not do it all the time.

Anyone else have this problem?


murf2222

I have been told by several including Mr XLR that the 'clicking' sound at idle is coming from the variable valve timing and is not anything to worry about. I have driven several ('04, 05 & 06) and currently own an '06 with 26K and I noticed the sound in most of them including my current car. The sound is similar to sound I remember coming from my VW TDI, just not as consistant - kind of comes and goes. True 'knocking' occurs during accelleration or load conditions - not at idle.

When all the 'experts' return from R-III I'm sure someone with more expertise can confirm this or disagree. Jon

I had an 2004 that did the same and after trying everything the dealer in fact drove it hard for 2 days and clreared the noise up.

They told me I wasn't driving hard enough... that said I have had over 20 Vets in life never had one knock from my driving..

Well, the de-carbonizing of the combustion chambers must have done the trick. Have only put about 75 miles on it so far, but so far so good.

Hard to believe that in this day and age where internal cumbustion temps are designed to be soo high that carbon would even have a chance to form. Hell........I've seen the temp gauge on this car get over 230 F before!
Oh well, at least I now have an excuse to *blow it out* periodically without getting the death glare from the wife.


murf2222

Hello, I ourchased an 05 XLR that I purchased May 08 that had only 30,000 miles on it. I had it for 6 months and now there is a knocking sound when you accerlate that is loud and very obvious. The GM Certified dealership has replaced every sensor and now has re-built the transmission and also replaced the Computer Modular system. I am completely frustrated. No one can seem to find what the problem is. It has pratically been in the shop since November and I'm tired of using a rental when I pay so much each month for this car. Any ideas. I'm so so tired of all of this!