Hello All, I.m having an idle problem with my car and any advice would be appreciated.

The car is a 1993 Mazda MX-6 with a 2.0L 4cyl and automatic transmission.

The problem is that when I start the car, after its been sitting for a while, it idles around 1500-2000 rpm. After a few minutes of this high (smooth) idle the idle speed drops fairly abruptly to no more than 500 rpm where it lopes along, sometimes dying. It won't go back up to the high idle until it cools down for a while. (hours)

I've tried quite a few things including replacing plugs and wires, inspecting intake boot, cleaning MAF sensor and throttle body, checking for trouble codes (none), testing IAC valve (idles even worse when connector is unplugged), etc. Nothing helped. I have also replaced the PCV valve and checked the EGR valve (seems ok, not sticking at least).

The car generally starts perfectly when it is cold, but after its been run awhile it becomes erratic to start. Sometime there is no ignition at all and sometimes it simply won't idle even though it does light off, immediately going dead.

I've been through all the forums but no one seems to have this exact problem, and I've tried most of those fixes.

Thanks