Hey guys, started working on my 96 f250 powerstroke again. The truck will be running and lose power, going into idle mode and will stay there until I release the accelerator and then go on. I was told that the PCM is doing a restart from losing power momentarily. It has had 3 pcm's same problem. Any thoughts would be appreciated. I have tried just about everything and cannot get it fixed.

 

My guess would be the pedal position sensor... for give me as I don't know the exact term.

But it could be a lot of other things too... best would be get a scanner on it and see what you get for sensor feed back

 

Hey lee00, I was thinking if it were the TPS that a code would be thrown. When it fails all I get is the WTS light flashes and it is in idle mode. I have been told the only thing that causes the WTS to light would be a power failure. Thanks, I might just try a new TPS.

 

Is the truck chipped ?

If the wts is coming on then the pcm is losing power.

 

Sounds more like an IVS. For a lack of better words, it can make the TPS signal drop out making the truck drop to idle. I can't remember off the top of my head how to check it but search IVS and there are a couple of threads that are really helpful

 

Sounds like the IVS to me too other than the WTS light coming on .

 

If the pcm loses power then Ivs will have to be repressed.
If you take the Ivs off and let it hang you can just click it and drive all day but after yiu shut of the power then it'll have to be clicked again.

 

Why would it need to be re pressed ? If its closed , its closed
Assuming it is working properly to begin with . PCM needs to see a closed IVS always .

 

I did a little test after reading your post . Started the truck with the go pedal matted . Shut the truck off & started it again . the IVS needed to be reset . You were right .Sorry .

 

Nice go see you around Rick
How have you been ?

 

Really appreciate all the replies. The truck is not chipped. I can duplicate the trouble with the ivs but I don't get the wts light. I have monitored the voltage in to the pcm with no loss of voltage when fault occurs, which tells me I could be losing ground. I was wondering if there is any condition that would light the wts other than lose of vpwr. Sure wish I could have a common fault that would set a code.

 

Are you 100% sure it's not chipped?
Possible causes
Lose chip
Bad wire to pcm
Bad connection at pcm
Lose/bad wire at ignition
Ignition out of adjustment

I'd start the truck and start shaking wires at the pcm then open up the steering column and start tapping wiggling the ignition and rod

 

Yea Mike. I am the second owner of this truck. Plus it is on it's 3rd pcm so no chip. I replaced the ignition switch(one with contacts), but I was wondering if the rod going down the steering column could somehow get out of adjustment or if the tumbler part of switch is not pushing the rod completely. This has been a bugger.

 

If the WTS light does not come on when this happens, the IVS is the prime suspect. Power to the IVS is via another fused circuit. Don't remember which circuit offhand; EVTM is out in the truck and it's pouring rain.

 

Post 3 states the WTS is coming on.