2001 Ford Expedition idle problems

Recently bought a 2001 Ford Expedition with 115,000 miles about a month ago. SUV runs excellent except for one thing: after driving the Expedition for awhile and warming it up, it will lose power while idling in gear at red lights. It does not stall, however; the engine revs up to get it back at the normal idle. Sometimes the idle problem will not occur at a red light, other times it will occur 4-5 times. This does not happen while the vehicle is in park, only when it is in drive. I have replaced the EGR valve and cleaned the throttle body plates, but the problem still persists. Also, when used at night, the lights inside the vehicle will dim when this idling problem occurs. Can anyone help me???

Thanks,
Boone Kinard

sound like a vac leak. check elbow in back of throttle body. sometimes its not obvious(ripped) but i had one that kicked my ass once i finally decided to put a hose clamp on it and the problem went away.

Thanks for the reply... I'm gonna check it very soon and see if that's the problem.

it's your pcv valve tube, this happened to mine also. found this info on an earlier thread and it was right on.