s10 idle problem

i have 88 s10. it has trouble running when i get it started. it will just die on me when i touch brake to put into gear it dies. when i can get going finally, i can let it idle then it runs rough then dies on me. i have to lightly hold down gas and put it in park or neutral at red light or stop sign. so far i have set the timing and that has not helped. i have looked in my haynes manual at the choke and turns out my 4.3 has throttle body. i have cleaned the throttle body with carb cleaner and it didn't help either. i was told that i have an electronic vacuum regulator valve or map sensor that could be going bad possibly. what are the symptoms of one of them going bad? how can i see if maybe i have a vacuum leak somewhere? thanks