Idling ? Please help

1994 4X4 3.0 V6 Automatic, 358000 miles, Truck runs great once it worms up, when I first start truck in the mourning now it wont idle, I got to keep giving it gas, was starting and idling fine up to a few days ago. Where should I start looking first?
Thanks
Joe

Nobody

I check the ECU and came up a code 55 witch means no malfunctions. Checking the code I would turn the key on, then turn screw fully clockwise, wait and the red and green light would blink 2 times and then it would blink 3 times, at that point I turn the screw fully counter clockwise. Then I got 5 red flashes and 5 green. Did I do this correctly?
Thanks
Joe