I have a 2009 Chevrolet Silverado 1500 LT Z71 4x4. Purchased the truck with 38,000 miles on it. I now have 58,700 miles on it. About 6 weeks ago, I started the truck and let it warm up about 15 minutes due to the extreme cold. I started driving it and put it in cruise control at 58 mph after about 8 miles of driving. I noticed that the RPM gauge would fluctuate between 200-300 rpms from 1500 rpms to 1800 rpms. It would stay at 1800 rpms a few seconds and then drop back down. It is doing this on a consistent basis. Doesn't seem to do it when not in cruise . The check engine light isn't on. I have had it tested for codes and no codes are showing up. The dealer said it was the AFM that was causing the fluctuations. However, it didn't do it when I first acquired the vehicle. Also seems to be cold weather related. Any ideas would be appreciated.

 

The research I did led me to believe that the Active Fuel Management was acting up. I have since taken care of the problem. My mpg went up as well. I will not be purchasing another vehicle with Active Fuel Management. In my experience, they don't do what they say and more people have had to rebuild engines over it failing.

 

There are a few threads on the forums similar to yours. Too much technology is not always a good thing.

 

Carl you said that you got the issue fixed, what did you do to fix it?

 

Carl I have received your email. I did find that item and am thinking aboutythe purchase.
Thanks and I'll let you know my decision in the future.