got a friends 01 and it takes about 20 seconds of cranking before the oil pressure gauge moves then it will fire, once running it runs good but will stall like you turned off the key every once in a while. hpop reservoir is full, could it be ipr?

on edit: once it does die instantly like that, even though there is oil pressure, it wont restart.

 

Why not measure the low-side oil pressure with a mechanical gauge?

 

Yes, it could be the IPR. I just went through that myself. It could be your ICP sensor too (much easier to replace...as in 5 minutes...and a little bit cheaper to buy). If standing at the front of your truck, it is on the engine block directly to the right of your fuel bowl, and slightly behind the left side of your alternator. You'll see the wire plugging into the top of it.

Unplug that, and then try to start the truck. When unplugged, it fools the computer into thinking the IPR needs 60% of pressure. If it starts up right away, it's probably bad. Also, if you see oil coming out of the top of that sensor (or the electrical connector has oil in it), then it's likely bad.

As far as your IPR is concerned, take it out and do the IPR rebuild. Basically, you are cleaning it and replacing the two o-rings (a #012, and 114). You're going to need a 1 1/8" socket for the IPR, but the socket needs to be 3.25" deep or deeper. NAPA sells them under part number NTD-36 (List price is $20, but I bought one for $5.25 last weekend without negotiating). If cleaning up the IPR works, then you're only out a few dollars. If you need a new IPR altogether...they're about $200. Ouch.

You'll want to check your Glow Plug Relay (GPR) too. Heck, it could be the starter. There's a lot to check.

 

tried to run the truck with the icp unplugged already forgot to mention that, im about to swap in a good IPR ill let you know what happens.