Oil pressure problems on 97

I have 97 powerstroke that I pull with I'm having problem with it when I take off it die out like its getting under the charger in 4 gear low 4wheel drive if I go up to 3rd gear it will go down the track but the high pressure oil side I have a gauge on and it goes up to 1000 psi and stays there I've put new icp ipr and engine harness had the duel terminators on it took them off put the gen3 on and still having the same problem.

If you're only building 1,000 psi of icp, you have a major high pressure oil leak. Probably injector o rings, or worn out injectors. Also could be an ipr sticking.

How could I check for leaks is there a way.

How high does the gauge read? 5000? First I would try a different gauge just to be safe. Then put shop air to each head separatly and listen for leaks.

Yes the gauge goes to 5000 how would do I get the air into the head.

Take a HPO line off and use a rubber outlet coming out of air gun, try to hold the two together and let air in the hose listen for leaks