Recently and intermittently my 1996 Dodge PU ( 12 Valve Cummins / 47RE automatic) when pulling out from a stop, will only accelerate up to 40 mph and not shift from 3rd to 4th. If I pull over, shut down and let it sit for a couple seconds then start up again and pull out, it will drive and shift normally. Any ideas? Does it seem to anyone like a transmission or computer problem. I took it into my mechanic, but he could not get it to duplicate the symptom.

Thanks

 

hi
first easiest thing is to replace the tps , common prob !

 

Thank you