A vehicle's ignition module controls the timing and functioning of spark plugs. The vehicle's performance is affected if the sparks plugs misfire or stop producing a spark. There are several signs that indicate an ignition module is bad.
The vehicle may shake, vibrate or jerk when the gas pedal is pressed. There may be hesitation or lack of power during increases in speed.
A faulty ignition module can cause a vehicle to overheat. The vehicle may run and then lose power suddenly due to a rise in the engine's temperature. Once the engine cools, the vehicle will start and run until it overheats again.
The engine may turn over without starting. Several attempts may be needed to start the vehicle and it will lose power again after it cranks.
