Had to do the cable shut off mod on my 92 tonight. Truck was shuddering and seamed to shut down/pick back up on the freeway...also wouldn't turn off with the key. I'll get a new solenoid soon but now the truck doesn't run like it used to. Had lots of power, but now it sucks! Runs smooth but doesn't seam to fuel like it should. Turbo still whines but not like it used to, I don't think its the turbo. Could I have rubber from the plunger in the lines somewhere? HELP PLEASE!!!

 

A couple possibilities - first off, did you disturb the throttle linkage when getting at the solenoid? It's possible you aren't getting full travel at the pump. Also you may have loosened/cracked the tube from the AFC to the cylinder head. If there's a leak there, the pump will not give full fuel.