The 4.5s does have a issue at the moment. A momentary loss of power with colder temps. The problem is with the computer misreading the tone wheel. A new flash has just been release to correct this issue. Not all the 4.5s have this issue.
On a side note, a new flash has been release for the '03-04s with the auto. Now you can have high idle control through the cruise control. With the truck at idle and in park you can turn cruise on and hit set will bump the idle to 1000 rpms, then hit accel will enable 1500 rpms. Turning off cruise or touching the brake pedal will disable high idle and drop back to the normal idle.
A forum community dedicated to Chevrolet and GMC diesel truck owners and enthusiasts. Come join the discussion about duramax engines, performance, builds, modifications, classifieds, troubleshooting, maintenance, and more!