My 98 Ranger has the 2.5 engine with manual transmission. 90 thousand on the odometer. Idle speed was slowing down to around 500 RPM and with the air on would hunt between 500-700 RPM. Pulled the throttle body this morning. It was really gunked up inside. Throttle blade was all coked up with soft carbon as was the bore. IAC valve was dirty too. Cleaned them both with CRC Throttle Body and Intake cleaner (Teflon safe). It's all bright and shiny now and the idle is rock steady at 700 RPM, even with the compressor engaged. Seems much smoother and quieter as well. Throttle response seems smoother as well. It had never been touched before. Guess it was overdue.