i am wondering if i buy this truck is there any performance chips for it...i know all the newer diesle are running edges im wondering if there is anything like that for a vehicle this old?

91 did not come stock with a turbo...as far as a chip, the truck has a computer (called a PCM...powertrain control module), but it is to operate the transmission (presuming it is an automatic). You can purchase/reprogram yours for better shifting, etc., but it operates nothing as far as the engine is concerned. There is no chip available for it. Jim

My truck has a 5 spd and no computers, which makes things simpler. I guess the automatics to have a pcm. There are several aftermarket turbo kits available for 7.3 naturally aspirated engines and people seem to love them. Really wakes them up. '91's have mechanical fuel injection so there is no need for an engine management computer.