5.9 12 Valve Cummins Diesel – Adjust Idle Speed
Correct Idle speed is: Automatic Transmission – in drive with AC on 750-800 RPM Manual Tansmission – in neutral with AC on 750-800 RPM NOTE: These speeds may cause stalling when the engine is cold. If this is occurs, adjust the idle speed to 900 RPM. The dash tachometer is not accurate enough for proper adjustment….