Still need help for 2003 7.3PS can't get it to crank

[m2b1969]

Alright here is the situation, I've got a 2003 F250 SD 7.3L PS w/ 209000mls. If I do not plug my truck in at night it will not start in the morning. It's cranking and acts as if it wants to start but doesn't.

Temps right now are in the 40's. However, the truck will not start without the blockheater plugged in unless I've been driving it for a while and does not sit for more than 4 hours. I have this problem even if it's in the 60's at night.

Here is what I've done, I've tested the GPR it was bad so I replaced it, it works and I get the proper voltage. This helped it tremendously wanting to start, but didn't help it get to starting all the way. I've replaced all glow plugs, and wiring harnesses with OEM equipment. I've tested the harnesses and glow plugs. All voltages and continuity is correct.

As I said when it is below even say 70 degrees, and the truck has been sitting for more than say 4 to 5 hours the truck cranks like mad, and wants to start, but will not start without me plugging it in. What in the world else could it be? Could it be the pre-heater in the fuel bowl by chance or am I grabbing at straws. Or even worse the PCM maybe. Don't know I'm lost now.

I'm losing my mind on this one. Any thoughts please.

[calfarley1]

Sounds like you may have a stiction problem with the injectors. I would try to change the oil and add 2 bottles of Revex. I have had many trucks with this same problem and it was the injectors were sticking when cold.

[m2b1969]

I'll revex it then. I've changed the oil and added B&G engine restore