Scotty, I have a 1995 F250 93000 miles 5.8 with a C6 that stalls when you put it in drive or reverse. If I disconnect the speed sensor on the rear end truck runs perfect. Only fault code are emission related (Air pump plumbing has long rotted off and has been bypassed). Speedometer works and no ABS code with sensor connected. Seems to me that if I had bad engine sensors that disconnecting the rear sensor should not make a difference. Someone out there must have run into this problem before. Thanks
You got the answer. Change the speed sensor.
Thanks, That was the first thing I did. Still had the problem. If the ABS shows no faults and the speedometer works wouldn't that mean the sensor is working?
If I step on the brake and raise the rpm just slightly above idle it will not stall when put in gear. So does something tell the engine to increase rpm when shifted into drive or reverse? The voltage readings to the IAC are within spec but I changed the IAC anyway thinking the mechanical part might be defective. It does Idle high on cold startup and idle decreases as it warms up so I think IAC is working? The TPS voltage checks are good. It has a MAP sensor (over 8500 gross wt). voltage checks are OK. Swapped that out also thinking mechanical, still have problem. (I do not see a hard wire from the neutral safety switch to the engine computer on the ford wiring diagram so I ruled that out). I had this to two different garages and they couldn't figure it out. At this point it's cheaper for me to throw parts at it than pay someone not to fix it. So if someone out there has a guess I'm willing to spend. By the Ford wiring diagram I see that the speedometer has one wire going to the engine computer. Wire has continuity. I cannot find anything on how the speedometer interacts with the engine computer ( would it be common 5v sense voltage?) Instrument cluster from junkyard is $35-40. Does anyone think that could be the problem? Truck is used for work around the farm so I run it with speed sensor disconnected. Truck is well maintained and I would like to make it road worthy in case I need it.