My 2001 RAM 2500 24V Cummins Automatic (56K Miles) goes from dead pedal starting at 2000 RPM in 1st gear to having the transmission disengaged above 2000 RPM. Sometimes I can rev the engine but it acts like the truck is in neutral. The truck will drive in first gear, as long as I stay under 2K RPM. I have replaced the APPS, same problem. The error codes are:P PCUCP 0720P ECUP 1693 Any help would be greatly appreciated.