My 1998 Ranger XLT 2.5L is idling so fast the truck runs @ 20mph in drive with the AC running. What’s the correct idle speed supposed to be?

 

Welcome to the forum

1998 2.5l should idle at 1,000RPM cold and then it will slowly drop to 750-800 when warmed up

Air increases RPMs not fuel, so if you have an air leak/vacuum leak, then RPMs will stay high

 

Thank you kind sir! For the welcome and advice.

I pulled the throttle cover off and inspected the vacuum hoses the I had replaced when I got the truck last year. They were all solid and intact. I removed the intake tube to check the filter and spray some throttle body cleaner down the opening when I noticed the flange wasn’t fully closed. Then I noticed that the throttle stop screw was keeping the flange from closing so I unscrewed the stop screw about 1 full turn and Voila! Problem solved. The truck idles @ 1000-1100 rpm cold and 750-800 warmed up. Just like magic.

No vacuum leak but too much air. Maybe I’ll get better mileage too. 😊

Thank you again for the advice.

 

Good work

Thanks for the update, and The Fix, it will help someone else down the road

 

A little thread necromancy here and I apologize for that.
However, my 2004 Ranger, extended cab, XLT, 4.0L, Auto, 4x2 was experiencing similar symptoms. A thread search brought this one to my attention.
A week before, I had traced a a/c controls issue to a broken vacuum line under the hood. In the course of my search for that vacuum leak, I had disconnected and removed the engine air intake tube and the PCV (I believe it is) tube that plugs into it. Today, after reading this thread, I went back and disconnected all those same points and reconnected them. Viola! Issue resolved!

You were indeed prophetic, Ron!