How do you change spark plug wires in a GM pickup truck It is a sierra classic 1500 with a 350hp motor It has 8 cylinders and an automatic transmission It was made in 1995 It is fuel injected?

Answer 1

Spray a little solvent around each sparkplug, then use compressed air to blow each one clean. That way you minimize the possibility of getting debris down the cylinder after the plugs are out. Mark the plug wires before removing them, usually a piece of tape with the number written on it or a wire marker with a printed number. Remove the plugs and note the color and general condition. If any of the plugs are black or oil fouled, that cylinder is burning a little oil. If any of the plug insulators are bright white, that cylinder is running "lean", and you need to find the vacuum leak and repair it. With all of the plugs out, run a compression test. Use a compression gauge in each cylinder and briefly crank the engine to make certain that all cylinders are functioning properly. You sould get about 110 to 120 PSI in each cylinder. If any are below 90, you probably have a valve going bad. Check the plug gap before replacing the plug. The proper gap setting should be written somewhere on a label under the hood. Make sure you reconnect the plug wires to the correct plug, then start the engine and drive off.