One of the most frequent ignition problems with the Ford Focus is bad coil packs. A faulty coil pack can make your Focus almost undrivable. It may also have no impact on the engine's abilities to perform. As they lose their ability to fire the spark plugs, things will become worse.
In older vehicles, coil packs replace the distributor and coil. They are told when to fire the spark plugs by the computer in the engine. The signs of a faulty coil pack are almost similar to those of a damaged spark plug. So much so that looking at the plugs first is a great place to start when diagnosing your Ford Focus.
It may well be costly to replace all of them if you need to. Using a multimeter, you can identify which coil pack is damaged.
There are a variety of symptoms that may be caused by faulty coil packs in your Focus. If your service engine soon light is on, we always suggest utilizing an OBDII scanner to pull your problem codes. It can help you focus your inquiry. If you don't have one, your local parts shop will gladly help you.
The following are the most frequent signs and symptoms of faulty coil packs:
- Check Engine Light
One of the most frequent signs of bad Coil Packs is the check engine light. Your engine's computer will most likely be able to identify faulty Coil Packs in your Focus.
There are several problem codes related to misfires.
- P0300– This failure code indicates that a random misfire has occurred. A random misfire occurs when the ECM detects a misfire but is unable to identify which one it is coming from or when the misfire happens at random.
- P0301 through P0312- These error codes suggest that one of the cylinders had a misfire. P0304, for instance, indicates a misfire in cylinder 4 of the firing order. This makes determining the cause of the misfire a little simpler.
There are other misfire related codes as well.
- Acceleration isn’t Normal
The fuel and ignition systems in your Focus react when you push the gas pedal. It must be apparent if acceleration has slowed. The fewer cylinders in your engine, the greater the impact of one cylinder not firing efficiently on engine performance.
If you have one or more faulty Coil Packs, the Focus' acceleration will be weaker, and you'll likely experience a jerking sensation.
- Fuel Economy
The less effective your engine's combustion, the more fuel will be consumed. As a result, the fuel efficiency decreases. When you bring your car in for a tune-up because of poor fuel efficiency, the ignition system (including the coil packs) will be one of the first things a technician will look at.
The most frequent indication of faulty Coil Packs is misfiring. Anything else you're experiencing is a consequence of the misfiring. What's really at issue here is what's leading the misfire. The coil packs are just part of the ignition system of your Focus. Spark plugs and plug wires are also included.
Misfires can also be caused by factors unconnected to ignition. This could be due to a lack of fuel pressure, faulty fuel injectors, or even a jumped timing chain (or belt). Since a vehicle can misfire for a variety of causes, we suggest checking for problem codes first.
- Rough Idling
While a Spark Plug is misfiring, it is most apparent when the engine is running at idle. This is because it is simpler to notice a slower-turning engine. A rough vibration will be experienced.
Conclusion: Bad Coil Packs Ford Focus
Be aware that nearly all of the signs of a damaged coil pack in your Focus could also indicate other ignition system problems.