I have a 97 Chevy Silverado 6.5L turbo diesel I have had it for a month and last week I started having this problem... when I start it and run it it does fine for 3 to 5 mins then as soon as I let off of the gas it falls on its face and loses all power. I can put the pedal to the floor n it does nothing. If I turn it off and then back on it will regain power for a moment but then falls on its face again... I replaced fuel pump and fuel injector... What should I check next?

 

Sounds like the pmd could be having some issues

 

Start with getting the trouble codes checked.

 

Yep, It does sound like the PMD is crapping out on you.

 

I think it sounds more like a fuel restriction problem or APP problem or defuel/limp mode.
PMD failure is stall or runaway-almost unheard of for a PMD to affect power.

Get the trouble codes checked!
Most parts stores do it for free-write down the code #'s and post them here.
We will help decipher them.