Fox14120

I've got an 97 Civic Ex (auto) 5 months ago my buddy replaced the Cylinder head with a new one after the gasket went (was atleast 2nd time that happened since the head was shaved atleast once before i got the car.) The car hasn't really been back on the road much since but has been taken out on test runs and also ran in the driveway for periods of time while ironing out small problems and issues and never had idle problems then. Last Sunday took it out on a semi endurance test (27 mile round trip test in mostly open area) The car ran fine for the most part but towards the end of the run had to stop at a light and the idle dropped and stalled. A few cranks of the key and it restarted but the idle remained lower (between 100-350 rpms) got it home no problem runs fine at speed but stalled again as i put it in park in the driveway. The next day went back to take a look at closer the car started up no problem but after a few mins as the car starts to warm up the idle goes from running normal around 700 rpms and drops to the 100-300 rpm range wether in park, drive, or reverse. Tried moving the distributer (was new last sept) either way and had no positive effect on the idle did make it worse evenually put it back where it originally was. Checked the IACV tonight pulled connector and the idle went up like it should so wasn't that any ideas on what else to check?