1992 G20 running problems. (confusion has sit in)

Looked through all threads, nothing matched exactly. So here goes. I bought a 1992 Chevy G20 van, after it had been setting for a year. I replaced rear brakes, and new master cylinder. Also a new fuel pump, assembley and filter. Drove it to Key West. Had the service light come on..didnt know code at time, however van would bog down, and i would have to floor it to get it going. At one point it died while cruising at 55mph. Once i would stop and turn off, it would reset the system and drive ok until the light came on. I figured the code was O2 sensor, so i replaced in Key west and didnt really have and issue. Oh and on occasion at first start up after it had been driven, it would start then die..and it would take awhile for it to start up and run. Made it back from the Keys..light didnt come on until almost 20 miles to the house. So it was fine for almost 400 miles.

Since then I have replaced, fuel snesor, egr, egr solenoid, another O2 sensor. I just rescently replaced egr/and solenoid..and now it runs ruff, hestitaion when taking off...and its still after having been driven...coming back out to start up, then it dies and have to crank and crank..evetually it will start...I am lost at this point,..other than taking it into the shop...

any help would be appreciated.

Have you considered a good ol' conventional tune-up? Plugs, cap, rotor and plug wires?
Your problems sound a lot like bad spark plug wires.

Yeah thats next on the agenda. The engine has only 22K miles on it, its a new crate engine so I figured I was good on a tuneup, but it was sitting a year. At this point who knows.

Just finished with Tune up. Drove it town, and back. Let it sit for about 30 mins and then fired up ran for a couple minutes then died out, and cranked for another 10 minutes before she fired up again. Stumped. Oh and new codes, 22, and 45...throttle position sensor, and O2 running rich at startup....Idk