At the end of my rope!!!!
 

I recently bought a 1994 Chevy, C2500 two wheel drive, 6.5 turbo diesel, automatic trans. It hadnt been used in awhile when I bought it. We charged the batteries and got it running. It was hard starting and would die when you drove it. After reading the post here I thought it had to be the PMD, it was still in the factory postition on the pump. I changed the PMD and relocate it on the bumper. That did take care of the dying problem but it is still really hardd to start. It always starts but you really have to crank it, probably 10-20 seconds. When its sitting there ideling it seems to run fine. No smoke, no unreasonable noise. When I try to drive it down the road there is a big lack of power, the transmition shifts hard and there is no overdrive. The SES light is always on. I've changed to LP, OPS,glow plugs, glow plug timmer, cleaned all the grounds and even added more grounds.The turbo waste gate is working like its suppose to. The confusing thing is sometimes it will start and run great but it usually dont last long like this. Ive checked the wiring harness, for wire breaks and didnt find anything. After talking to a friend I changed the crankposition senser and the first few times I started it it wored great and ran like a champ. I cant remember what brand of crank sensor I put on. Could it have gone bad in such a short time? It really seems like a timming problem somewhere but I cant figure it out. Any ideas? Thanks in advance.

Sorry forgot to add the only code I was getting was for the TPS. I did get a new sensor but it didnt help the problem. Thanks again for any help.

Sounds like u need a new ac delco lift pump and ops whats fuel pressure like with key on engine of a the brass t located in front of motor passenger side

AC Delco ONLY for replacement electronic parts-aftermarket CPS ect. are often bad right out of the box.

Any fuel leaks from the filter housing when sitting need repaired,o-rings fail over time and cause hard starts from air entry.

Electronic timing ever been checked?

You don't have a TPS you have an APP-electonic throttle peddle.
Don't rely on google for code info-the 6.5 is unique with code definitions and the proper codes for them are posted here if you search.