1993 GMC Sierra

Engine Performance problem
1993 GMC Sierra 6 cyl Four Wheel Drive Manual 156000 miles

When I start my truck it starts fine sounds good runs for about 30 seconds and starts stumbling then stalls, recently the engine light was on, checked codes, replaced TPS light went off, after that is when the stalling started.I have checked all conections, vacume hoses. Took air cleaner off, started it up and watched the injectors and looks like they are delivering correct amount of fuel, when it starts stumbling dont see any difference in fuel delivery, LOST< HELP, Mike
June 18, 2010.

Clean out the idle air control valve and EGR valve and adjust the TPS closed idle and WOT voltages

Jun 18, 2010.