RPM Dropping when coming to a stop

I have a 1994 4 runner with the 3.0 and 5 speed I picked up about a month ago. I've been trying to figure out this problem since I got it. After the 4runner gets to operating temp anytime I come to a red light or stop sign and press the clutch in the rpms will drop to around 250. If I come to a complete stop it will jump back up to idle. While at about 250 if I press the gas it stalls. I have replaced the fuel filter and it is now running better but still doing it. I also did the timing belt and idlers which also got it running better. I'm not sure what to do next. Could it be a vacuum leak that I haven't been able to locate or something else? Any info is appreciated!

 

Clean the throttle chamber and plate. That's the first thing I would do. If that doesn't help you may have to look at the idle control unit.

 

I was told by the previous owner that they did that. I'll have to check to make sure. Thanks! Is there a way to check if the idle control is working or not with out just replacing it?

 

Not sure on that particular vehicle but on many cars you can raise and lower the idle speed (temporarily) with a good, bi-directional scan tool. If it moves up or down when you command it to, it means it's working.

 

The idle air control valve is built into the throttle body. It uses coolant temperature to open and close it. It’s mechanical. An air pocket in the coolant, low coolant, or a clogged passage will cause it to not work properly. You can disconnect the hoses and blow air through it to see if it’s clogged.I would also check to see if the throttle position sensor is in spec too.

 

See if you're still getting vac to the EGR valve at idle.