So I've had a fun problem with my 96 7.3 it started about a month ago now, whenever i start it up its sounds and runs fine for about 5 minutes or until i try to drive it. now as soon as i try to drive it or it warms up from dead cold i lose throttle response and it runs really rough, if i were to floor it it would only go up to 1000rpm and stay there.

Once it gets hot it runs perfectly fine, but if it starts to cool down it'll do it again and ill lose throttle response.

I've talked to a couple people now and they seem to think its the pressure regulator, but before i go and part swap till i find the problem and possibly make it worse i wanted to try posting my problem on here.

Last night i pulled the fuel filter and changed it as well as clean the screen going into the regulator, there is some diesel on the intake but i don't know if it came from the changing of the fuel filter or if the pump is bad.
i changed the glow plugs last winter and while i had the valve covers off i checked all the harnesses for the injectors and they seemed to look fine back then, but that was 6 months ago.

 

How old is your oil? Since its starting to get cooler worn out engine oil will cause havoc with injectors if they are bad. Try putting a scanner to check out PID's.

 

i changed the oil when i got the truck on thanksgiving weekend last year, so by now its probably due to get it changed.

 

Supposed to be every 3-5000 miles. Lol
Try unplugging the ebpv.

 

I keep running this over in my head. If it runs correctly cold and hot but not in between....I would check the basic stuff first. Then check live data for eot I wonder if the eot sensor isn't having issue in the range its running bad. Live data when its acting up may wind up being key to figuring this out...