I need to go in for a smog check soon, but it wont pass because of idle speed. My truck idles at 1200rpm when warm. How do I lower it? I've tried adjusting the upper and lower cables on the throttle, but it seems to still keep the idle high.

 

do a search for this, i know it was just covered about 2 weeks ago here for the 3.0 motor, its a little flathead screw right above the throttle body

 

One week ago actually
https://www.yotatech.com/forums/f123/idle-speed-adjust-98479/

 

the idle screw doesn't seem to lower it enough, it bottoms out all the way to the right. I tried adjusting the cables a bit and can get it within the corrrect range (800) when its sitting there in the driveway, but after 10sec of driving it seems to go back to 1200 again. Maybe the spring mechanism for the cables is kinda grimy, i'll wd-40 it and try again.

 

If it runs at 1200rpm after warmup, and, when you manually force the throttle such that it is against the stop underneath, then I'd try moving the stop.

 

I turned it off, and pulled it wide open so I could get to that set screw underneath. I backed it out a few turns and it seems better now. Thanks

 

If that gets you through our smog checks, good. Note that that stop should not have to be changed, so the question is, what has changed. Keep an eye out for other clues and symptoms which you can deal with after SmogII.

Lots of good stuff on this forum, so perhaps later you can do a little reading.

Good luck.