2001 Tacoma cold starting problem (3.4 V6)?

Sometimes when I start my truck in the morning, it cranks, fires, and instead of idleing up like it should, it runs about 7-800 rpm (like it does at regular operating temp); a couple of minutes later, the idle will finally kick up, it normally runs about 1200 or so when it's cold, I guess because the engine is cold; basically, whatever is supposed to kick the idle up when it's cold is not working immeadiately. This problem is intermittent; sometimes it starts fine cold and idles up immeadiately, and I have never had the check engine light come on in the 102k that I've had the truck. I know 1 other person with a Camry that this is happening to. Any ideas? The truck runs great after it's started.