Fuel System:
* Fuel pump failure: The fuel pump might be failing, delivering insufficient fuel pressure. This is a common cause of sudden power loss. Listen for a humming sound from the tank when you turn the key to the "on" position (but don't crank the engine). No hum suggests a possible pump failure.
* Clogged fuel filter: A restricted fuel filter prevents enough fuel from reaching the engine.
* Fuel injectors: A clogged or failing fuel injector can starve a cylinder of fuel, leading to power loss.
* Fuel pressure regulator: A faulty regulator might not maintain proper fuel pressure.
Ignition System:
* Ignition coil: A failing ignition coil can prevent one or more cylinders from firing, resulting in significant power loss.
* Spark plug wires: Cracked or damaged spark plug wires can cause misfires and loss of power.
* Distributor cap and rotor: Worn or damaged distributor cap and rotor can interrupt the spark delivery to the spark plugs. (Applies to distributor-equipped engines; some 1995 F-150s may have coil-on-plug ignition).
* Crankshaft Position Sensor (CKP): This sensor tells the computer the engine's rotational position. A faulty sensor will cause the computer to not properly time the ignition.
Air Intake System:
* Mass Airflow Sensor (MAF) sensor: A dirty or faulty MAF sensor provides inaccurate air flow readings to the engine computer, leading to a lean or rich fuel mixture and power loss.
* Air filter: An extremely clogged air filter can restrict airflow and cause power loss. This is less likely to cause *sudden* loss of power, though.
Other Possibilities:
* Throttle Position Sensor (TPS): A faulty TPS might provide incorrect throttle position data to the engine computer, affecting fuel delivery and ignition timing.
* Vacuum leaks: Leaks in the vacuum system can disrupt the operation of various engine components and cause power loss.
* Transmission issues (automatic): Problems within the transmission, such as low fluid level, a slipping clutch, or a failing torque converter, can lead to a loss of power.
* Catalytic converter: A clogged catalytic converter will severely restrict exhaust flow and reduce engine power. This usually develops gradually, but can happen suddenly if the converter completely fails.
Troubleshooting Steps:
1. Check the obvious: Start with the simplest things first – check the air filter, and ensure the fuel tank has gas.
2. Listen for unusual noises: Pay close attention to any unusual sounds from the engine, transmission, or fuel system.
3. Check engine codes: Use an OBD-II code reader to scan for any diagnostic trouble codes (DTCs) stored in the engine computer's memory. This is the most important step!
4. Visual inspection: Inspect the spark plug wires, distributor cap and rotor (if applicable), vacuum lines, and other components for visible damage.
Without more information or diagnostic codes, it's impossible to pinpoint the exact cause. A code reader and a methodical approach to checking the systems listed above are your best starting points. If you're not comfortable working on your vehicle yourself, it's best to take it to a qualified mechanic for diagnosis and repair.
