Fuel System:
* Clogged Fuel Filter: This is a common and relatively inexpensive fix. A clogged filter restricts fuel flow to the engine, leading to hesitation and bogging.
* Low Fuel Pressure: A failing fuel pump, clogged fuel injectors, or leaks in the fuel lines can all cause low fuel pressure. This prevents the engine from receiving the necessary fuel for proper combustion.
* Dirty Fuel Injectors: Clogged or dirty injectors prevent proper fuel atomization, leading to poor combustion and a bogging effect. Cleaning or replacing them may be necessary.
* Bad Fuel Pressure Regulator: This regulates fuel pressure within the system. A malfunctioning regulator can lead to either too high or too low pressure.
Ignition System:
* Worn Spark Plug Wires: Cracked or worn wires can cause misfires, leading to a loss of power and bogging.
* Faulty Ignition Coil: The coil provides the high voltage needed to ignite the fuel-air mixture. A failing coil can cause misfires in one or more cylinders.
* Distributor Cap and Rotor (if equipped): These components distribute the high voltage to the spark plugs. Wear or corrosion can cause misfires.
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational speed. A faulty sensor can cause erratic engine operation.
Air Intake System:
* Mass Airflow Sensor (MAF) Sensor: This sensor measures the amount of air entering the engine. A dirty or faulty MAF sensor can cause incorrect fuel delivery, leading to poor performance.
* Vacuum Leaks: Leaks in the vacuum lines can disrupt the operation of various engine components, including the fuel delivery system, leading to a rough idle and poor acceleration.
* Clogged Air Filter: A severely clogged air filter restricts airflow, leading to a lean fuel mixture and poor performance.
Other Potential Causes:
* Transmission Problems: Issues with the automatic transmission (if equipped) can cause hesitation and bogging, especially during acceleration. This would require a more in-depth transmission diagnostic.
* Exhaust System Restriction: A severely clogged catalytic converter or muffler can restrict exhaust flow, leading to a loss of power.
* Throttle Position Sensor (TPS): This sensor tells the computer the throttle's position. A faulty TPS can cause incorrect fuel delivery.
* Computer Issues (PCM): Although less common, a faulty PCM can lead to a variety of problems, including hesitation and poor acceleration.
Troubleshooting Steps:
1. Check the easy stuff first: Start with the air filter, fuel filter, and visually inspect the spark plug wires for cracks or damage.
2. Check for vacuum leaks: Listen for hissing sounds around the intake manifold and vacuum lines.
3. Have the codes read: A scan tool can read diagnostic trouble codes (DTCs) stored in the PCM, which can pinpoint the problem. Auto parts stores often offer free code reading.
It's difficult to pinpoint the exact cause without further diagnostics. Taking your Blazer to a qualified mechanic is the best way to accurately diagnose and fix the problem. Provide the mechanic with as much detail as possible about when the bogging occurs (under load, at specific RPMs, etc.) to help them narrow down the possibilities.
