The coil pack for your Impala's engine consist of three small ignition coils that individually send current to your six spark plugs when the engine is running. Problems with the coil packs typically occur with time and from everyday use. However, damage to the coils often involves water that has somehow made its way into the engine compartment. A defective ignition coil may send limited current to your Impala's spark plugs or no current at all. As a result, the engine may start but run erratically. In some instances, your engine may backfire when you depress the accelerator pedal. Locating and replacing any one or all three of your Impala 3400's ignition coils is a job that you can do at home with a few tools.
Turn the ignition key into the locked or off position and remove it from the lock cylinder. Pull your Impala's hood release lever and raise the hood.
Locate your Impala's spark plug wires. The wires are made of black, flexible rubber and each of them connects horizontally along the front of the engine. Each of the spark plug wires also has a small number painted on it that corresponds to the spark plug that it powers.
Follow all six of the spark plug wires back, across the top of your Impala's engine. Upon reaching the wires' connecting points, you will see three small, round components that look similar to the cap on a can of spray paint. These three parts are your Impala's ignition coils.
