Sorry if this has been answered before i just can't seem to find a similar scenario anywhere... okay this i whats happening truck runs great on cold start with ac on and with ac off.... then as truck warms up runs low rpm on idle sorry i have base module gauge cluster(sr5 coming soon) with no tach so i can't give exact rpm... and when i turn on ac its even worse... so to fix problem i turned on ac when truck was warm popped the hood and adjusted the plastic hex screw for ac, turned it clockwise made it worse so i backed out couple turns and truck is idling nice and smooth.... so now i get in truck turn off ac and truck turns off..... i thought that plastic hex screw had to do with kicking up idle when ac on? but why is it affecting my idle with ac off? thanks in advance for the responses. 1989 ex cab 22re 5spd 4x4