I have a friend who has a 2004 3/4 ton truck with a 6.0L that is not idling correctly. We have cleaned the maf and replaced the maf with the same results. What happens is it starts up rough then idles at 500rpm. Then when you stop at a light or stop sign it surges between 500rpm and 200rpm. Today it actually died at a light for the first time. Any help that I can get is greatly appreciated.