Idle problem

[logo20]

I know there are a lot of post concerning idling problems, but I still can't find the problem in my car. I have a 89 240. the problem is that every time I start the car the rpm stay ~1600 for quiet a few seconds and then start to come down slowly. I"ve try a lot of stuff, checked the iav valve and tomorrow I'm gonna change pcv valve to see what happens. Also the car is running a little too hot,
I'll appreciate any help.

[turbo240sx]

check EGR too. the hose on the twin cams cracks and leakes causing a bad idle among with other things. yours may be differant

[95se]

My car had an idle issue just recently. When it was idleing the electric fan would kick on and sometimes the rpms would rise to like a 1K and it would also overheat sometimes..mainly had the problem when the outside temps were cold. I ended up having to replace the thermostat because it was stuck in the closed position.

[logo20]

about 3 months ago when I didn't pass emission test, a mechanic check the egr and it's good, I've also check all the hoses the they're good. I'm pretty sure the idle problem is related to bad emission, but I can't find the solution.