When I start my 92 4x4 in the cold the idle surges up to 3,000 rpms, and then surges anywhere inbetween 1,000 and 2,500 back and forth, up and down until it gets hot. Even if I start to drive it right off, the rpm's will still surge until the truck is warm. This may go on for 5 to 20 minutes sometimes. I've checked the idle control sensor, raidator fluid, and now I'm stuck. I don't know what to do or where to start. Can anyone offer any suggestions? Thanks in advance.

 

Adjust your TPS and clean the throttle body.
Any CEL codes?

 

Just for a little more reference...

Since it is the cold time of year, your rig will idle high when you first start it as it is trying to get up to normal operating temperature as fast as possible. Once it does, your idle should decrease substantially. Even when fully warmed up when rig still idles around 1K rpm's (because it is cold outside). In the summer time, I idle at 750 rpm.

Follow MTL's tips and see if that helps.

 

I cleaned the throttle body, and there are no codes in the computer. What about the surging, it shouldn't go up and down, when it idles. I mean it's like up and down, and up and down consantly? What's that about? Thanks in advance

M

 

Look for vacuum leaks (use some carb cleaner).
May have a leaky cold start injector.

 

Ok, I'll check that out, where is the cold start injector located?

M