95 Vortec spider HELP Please
 

I have a 95 S10 with a 4.3 Vortec. 165K It was running great and was my daily driver. One day it started using crazy fuel and running rough. I also had fuel in my oil. It turned out it had a bad nut kit. The line was leaking. I changed the nut kit and figured with the age I would also do a spider since I had the take off the intake and it is old. I got a BMG rebuild and a new nut kit. I installed both, changed the oil and the truck fired and ran immediately with absolutely perfect idle.

Problem. In Park or Neutral the truck will redline and is smooth as silk with no issues and will idle forever with no problems. As soon as I shift into R or D it will only go to 1500 RPM with my foot on the brake and my foot on the gas. I tried to drive it and it bogged down I pulled the intake and it was bone dry. I cycled the key a few times, popped the clip on the fuel lines and there was alot of pressure on the return side. I reinstalled and same problem. It will barely get out of it's own way in D or R. I nursed it to an Auto Zone and had it scanned and it was clean. It used a ridiculous amount of gas to go 26 miles and put gas back in the oil. I changed the fuel pump and filter still no change. The truck has had the cats deleted.

I am fairly sure I connected everything correctly and again it will idle and rev perfectly in P or N. I am so stumped and have been fighting this for months. I really need the truck and am funds limited at this time.

Any ideas or suggestions greatly appreciated.