2001 2.7 idle problem??

I own a 2001 4x4 with a 2.7 and auto trans. My problem is when I come to a stop my tach drops down to 700 and my idle is smooth, if I sit for 20 or so second at a light my tach drops to 600 and the truck developes a shake or rough idle, has anyone else experienced this? Does anyone know what to do to correct it? My local dealer says this is normal for the 2.7.

I have the '00 2.7 and the idle does suck sometimes. hell every once in awhile the idle jumps higher and makes the truck want to move.

isn't the engine idol completely controled by the computer, I know that you used to be able to control it when toyota used a carberator but I think since they came out with injectors the idol was pre programed in the computer, the only thing I can think of that would screw up the idol is maybe a bad sencor some where?

Check for the easiest things. Vacuum leaks. Dirty maf sensor. Maf sensor especially if have a preoiled airfilter such as a k&n.

Thanks, OBATDDSD, I'll check your suggestions.Would a dirty maf sensor throw a code, or only throw a code if it wasn't functioning? Second question, how would you recommend cleaning it?

On my 95 it there was no check engine light. On my friends he had a check engine light. Strange huh... Maf sensor cleaner in a spray can at Kragens or whatever auto store nearby. It appears to be a slight build up of burnt on crud. Dont clean while hot or engine running.