I recently bought a 92 auto 4wd ext cab. It has been nothing but a nightmare so far. Here are the symptoms. Runs smooth, starts with a half turn of the key. Truck has barely any power. Turbo kicks in and out at say a third throttle running down the road steady. Sometimes turbo will not spool up at all, other times it spools and pulls well. No black smoke ever. I replaced the lift pump, and it was worn out, spring shot and it could not manually pump at all. Replaced fuel filter, when I did this the plate above it came out as well. This seemed to only go in one way and there are no leaks. Lift pump / filter made no difference.
Could the injection pump be shot having to had made up for the weak lift pump? Would that cause the turbo not to work? Any ideas / help is greatly appreciated.

 

check your turbo for shaft play and see if it spins freely. also fill out your sig so we can see what we are advising you on

 

Turbo spins very freely, very small amount of shaft play in and out, none side to side.