LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1993 >> Forward Control 7.4 N >> Repair and Diagnosis >> Engine Performance >> Engine Controls - Specifications >> Fuel System >> Minimum Idle Speed
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Minimum Idle Speed

NOTE: Minimum idle speed adjustment can only be performed on the 7.4L engines. For minimum idle speed adjustment procedures, see ADJUSTMENTS article in this section.
MINIMUM IDLE SPEED (1)

Application RPM
7.4L
Auto. Trans. (2) 600-650
Man. Trans. (3) 675-725
(1) Idle speed with seated IAC is lower than specified if engine has less than 500 miles or when checked at altitudes above 1500 feet.
(2) Automatic transmission in Drive.
(3) Manual transmission in Neutral.
scientia non olet · About LEMON Manuals