idles up and down
 

hello guys, what causes idle to fluctuate up and down when first started ,then it evens out after about 5 minutes.runs fine while your driving,but when you come to a stop and sitting there it does it again.at night you can see your headlights on the car in front of you getting dim then bright as you sit there at a stop. new maf,plugs wires,temperature sensor, checked vacum hoses,cleaned iac still does this. its a 94 3.0 with only 101,000 miles any ideas??

I'm not really sure, mine has been acting up similar to this here lately. I'm in the same boat as you looking for an answer to this.

Although you said you cleaned your IAC that would still be the main suspect to me. See if its working properly by starting the truck and then unplug the IAC and see if the idle changes. If the truck is still cold the idle should drop when the IAC is unplugged.

I was gonna say the same thing Rob. I had to change out my IAC i got one for 38.00 at oreillys but thats because i worked there. I got a discount. Anyways my truck was idleing low and i took the iac off while it ran it quit. I first sprayed some carb cleaner not brake cleaner carb cleaner. It fixed it for a few days then went back to idleing crazy again, so i replaced it and it starts up no problems.