Gawd; For starters, pull the aircleaner and look down the tbi throat to see if the fuel is puddling up on the butterflies. Try to see the spray pattern, one of the injectors might be dirty or stuck open. Make sure all of the vacuum lines are solid and in place. Reach in and see if you can wiggle the tps. It should be nice and tight. Using a thin screwdriver, move the tps lever from the idle position. If you get no change in idle condition the tps could have failed sending a partial open signal to the computer. There has been lot of heat under that 15 year old hood and the tps connector is not the most robust I have seen. Mine came apart and crumbled in my hands when I was chasing a similar problem on my 87 K5. A new connector and tps solved the problem. Also a bottle of Techron every
2-3 months helps a lot. Another thought; I have had the O2 sensor go bad without throwing a code. This can make the truck run rich as well. Just some ideas. Good Luck, JR- posted
20 years ago