1993 hard time idling in drive

[85deuce]

So I'm helping my friend fix his car. The problem I've found is that when it's in gear it has a hard time staying alive. It'll go normal then almost die up and down. This is while it's warmed up. Is there anything that can cause this ignition wise? The spark plugs have been recently replaced. O2 sensor, Spark plug wires, Cap/Rotor ( Been a year ) Looks like they could use replacing. In park it idles fine. This is a 1.6L also. So what do you guys think? I'm struggling to figure this out. Also I was told that the car was doing this before the plug change but the problem came back. So I'm guessing wires? Help would be greatly appreciated. Thank you!

[speedy25]

I'm not thoroughly familiar with Toyota but in almost ALL fuel injected cars there is an idle control valve almost always called an IAC. Suprisingly few seem to know about it but its almost always the cause of ANY complaint about idling. Usually the problem can be solved by removal and cleaning. They get carboned up and cant regulate well or at all. Sometimes they do fail too.

-Pete

[85deuce]

Also when I do the diagnostic port. The check engine just flashes rapidly not stopping. Does that mean it's good to go?