does 1995 Isuzu pickup have an idle air control valve?

Hello, Yes they do, and they are normally a Honda interchangeable part, just FYI. The IACV may be the culprit, since failure can be more evident when the engine is cold. Look at the IACV and see if it is clogged, or leaking, but if this issue started as soon as the timing belt was replaced, have you not contacted the shop about the issue? They may have caused the issue, or it may be co-incidental.