My diesel feels like it runs out of fuel when it hits the govenor's limit in the injection pump(probably exactly what it does,shuts off the fuel!)or like you shut the key off,until the motor slows down enough,then it turns back on again--my TH400 makes my truck do this quite often--the electric downshift detent switch tells the tranny to go back into first gear at too high a speed if your not careful--it zooms up to 35-40 in first,then boohhhhgggggss out when the govenor kicks in,then goes into second with a lurch of power--it gets annoying somtimes--feels like it needs another gear inbetween second and first!.I have the vacuum modulater hooked direct to the vacuum pump too,that might be a factor too-- /forums/images/graemlins/crazy.gif