High idle problem

[wranglercory]

I have a 87 MJ with a 2.5L AX-5 trans and just the last two days Ive had a problem with the idle being to high. I have done nothing to the truck and it just started to idle high yesterday. I tried swaping the injector it is a throttle body injection system. Does anyone have an idea what could be causing this to happen. I was thinking it is the sensor on the rear of the throttle body but not sure I tried disconnecting it last night when I got home but didnt seem to change anything I did disconnect it while it was running. Any help would be great.

[Pete M]

look for vacuum leaks. :thumbsup:

[wranglercory]

forgot to add that the truck sat idle for two days, then problem started on the third day when I started it and went to work. Ive used starting fluid, to see if there was a leak just in case but no leaks.

[1987Comanche]

Bad Idle Speed Controller.

[wranglercory]

I wondered if the ISC was the problem I have messed with it a little and looks like it could be it. Ill have to check online and find one.