K 1500 Truck 4WD V8-454 7.4L (1988)
2. On 1987-89 models, check base timing (Spec. 4 degrees BTDC).
View A
View B
3. On 1987-88 models only, relocate map sensor to air cleaner.
A. Check map sensor operation using procedures on pages 3-122 and 3-123 of the 1991 Light Duty Fuel and Emissions Manual; replace sensor if
necessary.
B. Disconnect vacuum tube assembly and electrical connection from map sensor.
C. Remove map sensor from upper plastic bracket (see illustration, View B). CARE MUST BE TAKEN TO AVOID BREAKING BRACKET.
D. Remove sheet metal screw holding upper plastic bracket to lower metal bracket, and retain plastic bracket.
