Hi, I have a 98 K2500, 350,4L80E. Bought it worn out at 185,000 mi. Had engine rebuilt and tranny rebuilt at different shops. All ok now except: (1) fuel milage down to 10 mpg from 13 (2) if truck is pointed engine downhill and under load, it won't bach up. Tranny doesn't slip, it just acts like engine doesn't have enough power to move it. any ideas?