IAC Valve Questions

Getting P0505 on my code reader. Was very cold this morning, started the truck, idled fine for a couple of seconds and then acted like it was being starved for fuel or air (running rough) and the CEL came on (P0505).

Recently did a head gasket and valve shimming so it could be something else but it ran fine yesterday (except maybe a bit of a high idle) when the temp was 50-60 deg. This morning it was 25 deg.

I cleaned my IAC recently (when I did the H/G) because it has been giving me some idle issues previous to the H/G (sometimes low, sometimes high) and seems weather/heat dependent. It seemed to act fine when it was hot outside but act up as the temp would get cooler, but never to this degree.

Looking at replacements, are the manuals and auto's different? If so, in what way?

I see plenty of cheap replacements for the auto, but not so much for the manual transmission.

Any ideas?