Can a bad IAC cause the engine to not want to idle high enough or?

Does it just cause a too fast an idle? My engine just doesn't want to idle up like I like it to. It will only idle at near stall rpm about 700-800 or less. Sometimes it will idle normally but then it'll drop down again. I'll swap it out tomorrow but before I did I was wondering if it could be the cause. I've got new O2's and normal air flow and fuel pressure.

Have you checked your motor mounts.
If they are bad, they rattle the Knock Sensor.This retards your timing.
The result is a stumbling idle.

I've never seen an IAC cause excessively low idle. An easy way to test if it is working or not is to pull the plug while the engine is running and see what happens.

I tried that and it didn't change. I've changed the MAF sensor now and it seems to be Ok and back to normal but there could still be a problem. I'll be running more tests this week. I've got a whole list of things to check. I'm not getting any codes anymore at least.