Ok, let me catch you all up to the events leading to my newset problem. Purchased this truck running on the passenger side 4 cylinders. Diagnosis confirmed faulty valve cover gasket. Replaced valve cover gaskets, uvc harness and all 4 connectors. While I was there also replaced the glow plugs using Motorcraft BERU's. Fixed that problem and truck ran great.
Next problem, when in park and you stab the gas the truck would sputter at 2500 rpms for a few seconds, smoke real bad then go to redline. (BTW, this is not something I do all the time, not even sure why I did it this time but I did and thought this needed to be corrected). Anyways, I don't have any diesel diagnostic tools so I took a stab at the injector o-rings considering the mileage 204,000 miles. Bought the correct Alliant o-rings and replaced all o-rings on all injectors. This is where the newest problem started.
After replacing the injector o-rings, when the truck is cold it has a long crank time before starting. Thinking possibly the glow plug relay has failed or is weak with 8 new glow plugs, I jumped the relay on the next cold start, waited 10 seconds and gave it a try. Same thing. I should start here and say I do not drive this truck everyday, I have not even registered yet as I try to work all the bugs out. So in other words this truck sits for days at a time in between starts.
Ok, back on track here. Still have the long start. Thinking there may be air in the fuel system, I thought I would hook up to my 26' horse trailer and drive around the county under a good heavy load and see how she does. Sunday I hook up the trailer and go for a ride. No problems and seems to have decent power. Unhook the trailer and park the truck. Today, tuesday I need to go check on 3 newborn colts so I thought I would drive the diesel truck. Long start, she starts but is missing so I drive down the road and after 1 mile realize this is not getting any better so I turn around and park it and take the gasser. Get back about 1.5 hours later, truck starts right up and is not missing. Take her around the block and giver her hell and everything is great. So now I have no idea. Is this a symptom of air in the fuel still after replacing the injector o-rings (maybe 40 miles ago) or could this be a HPOP problem. I think I am going to start assembling the tools needed to check the hpop system pressures.
Anyone got any suggestions. I know I don't have any hard diagnostic numbers, but I am working an getting the tools so I can sound more like I know what I am doing. Any help is greatly appreciated.

 

You might still have air in the system. You have to drive it to purge it. Secondly, when jumping the two posts on the GPR, you need to do it longer than 10 seconds to get a true test on it. Lastly, does the truck start fine if you plug it in? Also, the next time it sits for a while, check your HPOP reservior and see if you are 1/2" from the top. Low HPOP can cause a hard start as well.

 

Thanks for the suggestions. I have yet to plug the truck in but that is a great idea and I will try that. I will also try leaving the jumper on for a longer period. I think I will let the truck sit out tomorrow and on thursday I will check the hpop reservoir. I will chime back in with the results. Thanks again

 

No problem.