My 88 runner idles at roughly 600 rpms in gear but stopped... Sometimes the idle drops lower and it stalls out, usually when I come to a red light.. replaced air filter, not sure what to do?

 

When was the last time it was tuned up? It might just need new plugs, wires, cap, rotor and filters. Also check the ignition timing, adjust the valves, and clean the throttle body. Other problems could be the EGR valve, TPS, or vacuum leaks. If it is carbureted check the vacuum advance. If that does not work and it is otherwise running well, you might just need to turn up the idle speed a little.

 

I have an '88 what engine?

Mine is a 22re with a hot rodded 3mm overbore TB and after 24yrs I think IACV is shot. mine gallops when warm & that may be your whole problem. its underneath and a bit of a pain to get to.

What have you done and when?