Last night my truck was running slugish. After I stopped and started again it was normal. This morning it was slugish again so I turned it off and then right back on normal again. I haven't had any time yet to troubleshoot but if some one has had a similar experience let me know what you found.

Hard to say. How cold was it.

You could be resetting a sensor.

The temps are from the 30's at night to the 50's durring the day. Which sensor is capable of setting the truck into limp mode? The sensor on the crossover is new, so should suspect the one in the head?

The sensor I'm thinking of is the optical or CPS.

I could bump the optical back to the stock position to see if that changes the problem, but it's been running great for months with the optical set where it's at. Unless its just decided to go bad. I'm not familiar with the CPS. Additionally I noticed when it's running in limp mode the engine runs about 10deg. higher than usuall. Temp goes back to normal when out of limp mode. Thanks for info.

Whatever the problem is it is related to a sensor which is sensitive to being cold at start up. Twice today hours apart when I started for the first time I was in limp mode(ran for about 30 min.). Then turned off and right back on and was back to normal.

Will this is what happened to me.
I bought a 97 6.5 5 spd and it ran great. The next day i was heading to a job 500 km away from home so i changed the oil and fuel filter and was on my way. I get 35 km on the road it starts surging and feeled like i had no turbo. The whole trip was like this. So i started it the next morning and it stalled it was cold though but 10minutes after running it died.
So i fulled it upand as it was idling there it dies. Whatever Right!!!
The service throttle soon light come on and it died again so i start it up and it run good awesome the turbo i could hear it and was happy.
I take it to the jobsite one day and it idled all day and then at 2 pm it stalls and bucks and i run it to shop.
They Changed the filter fuel and 2 glow plugs and said have a nice day.
The truck has run great for 3 weeks now but i am aint an dumbass i know it aint a filter and 2 glow plugs why it was bucking and surging and stalling right?
What do you guys think it could be?

Thanks

Flanman, check your lift pump and fuel filler cap for starters.

MDT, I would take a good look at those two sensors and maybe try replacing the cheapest one. At least it's a place to start trying to figure it out.

The wires on the optical could be loose in the connector. My truck did this when the pump was failing from intermittent optical. It would act up and then act normal again. It could also be cloudy fuel or water in fuel. The oiptical losses track of the high/low resolution and goes limp 'till you restart it.

Thanks I'll check for water and loose connections on the optic. How much water could be in the system without turning on the water in fuel light. What's the CPS? The night before this happened I filled the tank could bad fuel cause this prob? Could the fuel be cloudy at start-up causing limp mode then once the engine warms up(maybe clears up) and is restarted goes back to normal. The condition will not change while running from bad to good or from good to bad so I'm pretty sure this is some signal that the PCM recieves at start-up, hopefully this will help narrow down potential problems.