Tune up a 1996 Chevy Blazer with a 4.3-liter engine at least every 30,000 miles, or when the vehicle misses under acceleration, the fuel economy drops off sharply, is hard starting or runs rough. The engine is fuel injected, so there are no adjustments for this system. The ignition system consists of the distributor, distributor cap, rotor, ignition control module, spark plug wires, spark plugs, crankshaft sensor, camshaft sensor, knock sensor and the engine control module.
Turn the ignition key to the "On" position, and observe the "Check Engine" light. The light should be illuminated on the dash, if the bulb is good. Start the engine, and observe whether the "Check Engine" light is off. If it remains on, a failure within the engine controls has occurred. In response, the computer has stored a failure code. The failure code will distinguish the part and briefly describe the irregularity. Plug the code scanner into the OBD (on-board diagnostics) port, located under the dash, on the left side of the steering column. Turn the key to the "On" position, and press the "Read" key on the scanner. The scanner will respond by displaying a five-digit code. Record this code, and cross-reference it with the scanner accompanying code sheet. The code sheet will describe the problem. Repair this fault before proceeding.
Lift the hood, and start the engine. Spray a mist of water on the spark plug wires. Look for any arcing, indicating defective or shorting plug wires. Replace them, if any arcing is observed. Turn off the engine, and allow it to cool.
Remove the air duct and air cleaner, using the screwdriver. Hold the new distributor cap next to the distributor, and make sure it is oriented in the same way as the one on the distributor. Transfer all the spark plug wires from the old cap to the new cap in a clockwise direction, one at a time. The must be put in the same place on the new cap. Move the new cap with the wires to the rear of the distributor, next to the firewall. Remove the distributor cap from the distributor, using the screwdriver. Discard the old cap.
Pull the rotor off the distributor shaft, and replace it with the new rotor. Install the new distributor cap, and tighten it with the screwdriver.
Pull the spark plug wires off the spark plugs, one at a time. Remove the spark plug with the spark plug socket, and replace it with a new plug. Install the spark plug wire, and proceed to the next one, until all have been replaced.
Pour the can of fuel injection cleaner into the gas tank. Start the engine. Spray the can of carburetor cleaner, slowly, in bursts, into the throttle body. This will clean the idle air control, the throttle plate and the intake manifold of carbon buildup. Install the air cleaner and air duct, and secure them with the screwdriver.