92 pickup. When i first start here in Mi. About 50 degrees Fahrenheit the truck idles at like 1800 rpm for about 2 mins. Then i can bear the fan kind of calm down a bit then another say 2 mins it seems like its "warmed up" and wants to idle down to its normal rpm, only thing is that the "normal" or "average" on my truck is like anywhere from 1100 to almost 1500 rpm. What could be causing this? Attached is a photo. If i push hard on that plunger i can get it to idle down some but not exactly to par. Once i let off it goes back up in rpm? Thanks for the help!

Arrow is pointing to the plunger that i push hard on to get to idle down.

 

The item you've circled is the "throttle opener." It should retract (vacuum) when the engine is running. When you turn the engine off, it extends (opening the throttle) to prevent dieseling.

Check that yours retracts with vacuum. With the vacuum disconnected (permanently extended) the spec is 900-1800 rpm http://web.archive.org/web/201108151...93throttle.pdf About what you're getting.