1988 GMC C1500

if this is tbi there are couple things that normally go wrong with them. first spray choke cleaner around the bottom of the tbi unit. if the idle changes , the gasket is leaking. also the hose going to the map sensor gets soft and sucks together not allowing the map to work right. really there isn't enough info to give you any other ideas. we need to know more than it doesn't run good..

Yes it is a tbi i believe it is a 4.3 , we have sprayed carb cleaner down and around the throttle body, we didn't notice any difference. This was before we asked the question, the engine will stall out unless u turn the steering wheel back and fourth or hold it to one side ,we have also noticed that at one point when we took the cap off the power steering pump it stayed running, I don't know if this was just by coincidence, because we were spraying in and around the tbi,we have also replaced the serpentein belt , distributor, cap, and rotor,the exhaust from the manifold on back, we didn't put the sensor in the crossover, I also jumped the diagnostic plug but there wasn't any trouble codes stored,I will try spray around the tbi again and probably replace the gasket anyway, and check the map sensor hose. If u can think of any thing else let me know please,thank-you