Matrix cold weather idle

[poizone]

I just inherited the family matrix, an 04 XR 5 speed with 170000. Living around cleveland as we do, the cold weather has always been a bit of a problem with idle after the engine has warmed up. Now that she is mine to take care of, I decided to see what I could do. I replaced the plugs at first, cause the old ones were pretty bad anyways, and checked the coils for cracks. Coils were fine, and she ran with a nice 800 idle for a few days. All of a sudden, she started to go down to 600, 500, and even dropped all the way below 400, and almost stalled out.

I adjusted the idle set screw, just a tiny bit, and now my idle is between 800 and 900. I know this is a little high, but other than the extra gas, is there a problem with leaving it? The ECU seems to be keeping the idle a lot more stable now, especially after coming down from a high rpm run, like 4k-6k to idle.

[circuitsmith]

Try cleaning the throttle body, cleaning or replacing the PCV valve and pouring a bottle of Chevron Techron fuel system cleaner in the gas tank.

[Tech1984]

I'm betting you have a deformed (shrunk) intake manifold gasket. Quite common.

[hardtopte72]

I second the intake gasket. And also since it is an 04 clean out the IAC valve as well.