The engine is stalling badly. It will do it at medium speeds ( 3 times now). It almost seems like the fuel supply is cut off then turned on. The engine has not completely stopped, but it stalls pretty bad. On all 3 cases I was almost where I was going so I don't know how long it would have lasted or if the engine would have died if I'd kept going.

Is this a typical symptom of a failing fuel pump or could it be something else?

 

It's a typical symptom of a lot of things, we're going to need to narrow it down a little more. does it a stall when cold, or warmed up , or both ? You will need to check the fuel pressure at the fuel rail fitting on the passenger side of the rail....it looks like a tire valve..a fuel pressure gauge works best but a tire pressure gauge will work in a pinch. When you turn the ign key to the second "on" position you should be able to hear the fuel pump run for a few seconds and you should get a pressure reading of 32-36psi at that fitting...low pressure there could be a failing pump OR a clogged fuel filter. What sort of maintenance has been done to your truck ? keep us posted on how it goes.

 

Maybe, but it sounds more like a bad TPS. Unplug the TPS and drive it, if it runs ok replace TPS. Report back with results.

 

It stalls when running at normal temp. In fact, I noticed the temp is slightly cooler than normal; just under 9'oclock. I know that gauge well and I'm sure it's just under normal. Does this mean anything? I'll do the pressure check as soon as I have a chance. The fuel filter was changed 13 months ago.

 

Listen to Higgs. Does is feel like a bank shuts down for a few seconds then you take your foot out of it, press the pedal again and it comes back? If so, it's the TPS. Unplug it, it's on the drivers side of the tranny, you won't have a speedo but it's an easy way to diag that particular sensor.

 

That is the Vehicle Speed Sensor -VSS

The TPS - Throttle Position Sensor- is on the side of the plenum beside the IACV is it not?

13 months ago = new fuel filter time.

 

Oops, see, a week without my Disco and I turn even dumber.

 

Time to get another...