I have 2003 2500 quad cab 4x4 ram with Hemi and 5 speed manual. It has this strange problem while towing where on occasion it just slows down like it is running out of power. It has never thrown a code when this happens and I have checked/or replaced usual things like fuel pressure, iat sensor. Usually the problem goes away after few miles and then sometimes it only goes away after restart. I frequently haul 7x12 dump trailer loaded with firewood and easily cruises at 70+ but when acting up can barely get it in 5th gear. Any thoughts on possible issues? Can the drive by wire system be the cause?