1994 GMC Forward Control 7.4 NFACTORY OEM SERVICE PROCEDURE

General Specifications & VIN Identification

1994 MODEL COVERAGE

Model Body (1) Engine Engine ID Fuel System Ignition Systemn
Astro & Safari M,L 4.3L (LB4) Z TBI Magnetic
M,L 4.3l (L35) W CPI Magnetic
Blazer & Yukon K 5.7L (LO5) K TBI Magnetic
K 6.5L (L56) (4) S Turbo Diesel N/A
Lumina APV, Silhouette, & Trans Sport U 3.1L (LG6) D TBI Magnetic
U 3.8L (L27) L MFI C(3)I
Parcel/Delivery Commercial Van & Motorhome P 4.3L (LB4) Z TBI Magnetic
P 5.7L (LO5) K TBI Magnetic
P 6.5L (L57) (4) Y Diesel N/A
P 6.5L (L65) (4) F Turbo Diesel N/A
P 7.4L (L19) N TBI Magnetic
Pickup (C/K 10/35) & Sierra C,K 4.3L (LB4) Z TBI Magnetic
C,K 5.0L (LO3) H TBI Magnetic
C,K 5.7L (LO5) K TBI Magnetic
C,K 5.7L (LO5) K CNG (2) Magnetic
C,K 6.5L (L65) (4) F Turbo Diesel N/A
C,K 6.5L (L49) (3) P Diesel N/A
C,K 6.5L (L56) (4) S Turbo Diesel N/A
C,K 7.4L (L19) N TBI Magnetic
Suburban C,K 5.7L (LO5) K TBI Magnetic
C,K 6.5L (L65) (4) F Turbo Diesel N/A
C,K 7.4L (L19) N TBI Magnetic
S/T Series Blazer, Bravada, Jimmy, Pickup & Sonoma S,T 2.2L (LN2) (5) 4 MFI Magnetic
S,T 4.3L (LB4) Z TBI Magnetic
S,T 4.3L (L35) W CPI Magnetic
Van (10/35), Rally Van & Vandura G 4.3L (LB4) Z TBI Magnetic
G 5.0L (LO3) H TBI Magnetic
G 5.7L (LO5) K TBI Magnetic
G 6.5L (L49) (3) P Diesel N/A
G 6.5L (L57) (4) Y Diesel N/A
G 7.4L (L19) N TBI Magnetic
(1) Engine code is stamped on engine block. See ENGINE CODE LOCATION .
(2) Compressed natural gas, limited information available.
(3) Light Duty emissions.
(4) Heavy Duty emissions.
(5) 2WD only.
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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