I have 2003 Ford Ranger with 4cyl. 2.4 liter eng. I recently cleaned my K&N air fliter and now the engine is revving up to about 2000 RPM and then it will drop to about 1000 RPM and idle at that RPM. It has never done this before. Does anyone have any suggestions? Thank you, Jack

I have a 88 ranger with a 2.3 EFI with a high idle problem. But mine slowly returns to normal idel after about 2 to 3 min.
Is this normal? I've had a real high ideal for a bout a year until i replaced the IAC,TPS, and O2 senser. I have an idea it might be the coolent temp sending unit. Well what do you guys think...

Sounds like a winner. If the ECM thinks the engine is cold, it will keep the idle high. What is your coolant temp gauge reading though?

__________________
Sgtsandman's Work in Progress
2011 Ranger XLT, 4X4, 4 door Super Cab. 4.0L, 5 Speed M50D-R1HD, 3.73:1, 8.8" open differential, Jason Pace cap
2019 Ford Ranger STX FX4, Super Crew, 2.3L Ecoboost, 10 speed automatic, 3.73:1 with rear locker, Leer 100XR cap

I have found out what was causing the fast idle. It was the idle control valve. An easy fix!!! Thank you for the suggestions!