Troubleshooting a car engine to determine why it's losing power is a challenging undertaking simply because of the complexity of car engine system. However, engine power loss is typically the result of fouled spark plugs, a failing fuel pump or a damaged ignition coil. Examining each of these components will help diagnose the problem so proper repair procedures can be implemented. Knowing where to start troubleshooting is half the challenge, and actually implementing procedures is straightforward, requiring only a few common tools.
Park the car on a flat service in an environment, such as a garage, where you're comfortable to work and pop the hood. Disconnect the black boot from the negative battery terminal.
Consult your vehicle's owner's manual for the location of the engine spark plugs and ignition coils. Remove the spark plug cover by unfastening the mounting screws or bolts, depending on the model, with either a Philips screwdriver or socket wrench and socket.
Take note of where each spark plug boot is plugged and where each spark plug is fastened because they will need replacing in the exact same position. Disconnect the wiring of each spark plug by firmly pulling it off the plug by the wire boot.
Remove each spark plug using a socket wrench and socket. Closely examine the plugs for signs of damage and unusual wear. Replace any damaged spark plugs with an identical plug.
Consult the manual for the location of the accelerator cable, which should be located near the spark plug holes. Unfasten the accelerator cable bolt with a socket wrench and socket. Disconnect the cable from the ignition coil pack.
Remove the ignition coil pack mounting retaining bolts with a socket wrench and socket. Carefully lift the ignition coil pack off the engine. Thoroughly examine the ignition coil for signs of damage such as cracks, burn marks and wear. Replace the ignition coil if visible damage is present.
Reassemble the ignition coil and spark plugs. Plug the wires into each spark plug by pushing on the wire boots. Reconnect the negative battery terminal and lower the car hood.
Consult your owner's manual for the location of the fuel pump. Remove the bolts from the fuel pump cover with a socket wrench and socket. Locate the fuel rail and connect a fuel pressure gauge to the end.
Start the car and inspect the fuel pressure gauge for a reading. Consult the owner's manual for proper pressure and compare it to the current reading. Rev the car engine while checking the fuel pressure gauge and take note of any discrepancies in the reading.
Allow the car to run until the time the engine typically loses power while examining the fuel pressure gauge. Replace the fuel pump if the fuel pressure gauge shows inadequate fuel pressure or shows signs that the fuel pump loses pressure over time.
Take your vehicle to a certified mechanic if the problem persists or if nothing is visibly wrong with the spark plugs, ignition coil or fuel pump.
