An engine functions as a pump, requiring a precise combination of fuel, air, and spark. If any element of this trio is imbalanced, your Nissan Altima won’t run right (or at all).
An engine functions as a pump, requiring a precise combination of fuel, air, and spark. If any element of this trio is imbalanced, your Nissan Altima won’t run right (or at all).
While a misfire is the symptom of bad spark plugs, bad spark plugs almost always indicate a problem with the engine (more on that in section 2).
The fundamental design and function of spark plugs have remained broadly consistent over the past century. In the Nissan Altima, they are positioned atop the combustion chamber and ignite the air-fuel mixture, initiating the engine’s power stroke.
Something that has changed about modern spark plugs is that many of them use iridium, don’t need to be gapped, and can last for 100k miles with little issue.
That being said, they still can go bad. The good news is that if you do need to replace your Altima’s plugs, they are very affordable.
There are a lot of potential symptoms related to foul spark plugs in your Altima. We always recommend using an OBDII scanner to pull your trouble codes if you have a check engine light on. It can really narrow your search down. If you don’t have one, your local parts store will do this for you for free.
It is also worth noting that the symptoms of bad spark plugs in your car will be almost the same as any other bad part in the ignition process. Bad coil packs will produce the same results and feel like bad plugs.
The check engine light is one of the most common symptoms of bad spark plugs. More often than not, your Altima’s computer can detect bad spark plugs in your car.
There are several misfire-related trouble codes.
As you ask your Altima for more power, the fuel and ignition systems respond. If acceleration has diminished, it should be felt. The fewer cylinders that your engine has, the more that one cylinder not firing correctly will have. If you have one or more bad spark plugs, it’ll cause the acceleration of the Altima to be weaker.
The less efficient your engine’s combustion, the more fuel will be wasted. This leads to a decrease in fuel economy.
When you take your Altima in for a tune-up due to decreased fuel economy, checking the spark plugs (and ignition system in general) is going to be one of the very first places a mechanic will look at.
Misfiring is the most common symptom of bad spark plugs. All of the other symptoms are a result of the misfiring itself. The real question is, what is causing the misfire? There is more to your Altima’s ignition system than just the plugs. There are also coil packs and spark plug wires.
There are also non-ignition-related circumstances that can cause your Nissan Altima to misfire. That would include a lack of fuel pressure, bad fuel injectors, or even a timing chain (or belt) that has jumped. Since there are so many reasons that a vehicle can misfire, we recommend testing for trouble codes first.
When a spark plug is misfiring, it is often most pronounced at idle speed. This is because when your car’s engine turns slower, it is easier to detect. You’ll feel a rough vibration.
There are two parts to diagnosing bad spark plugs in your Altima. The first is to identify the misfiring cylinder. The second is to inspect the plug. If it looks ok, follow the diagnostic steps listed below. If it doesn’t look ok, use the chart below to determine why the plug has gone bad.
If your Altima has a cylinder-specific misfire code, you can swap parts to diagnose what’s failed. You will need an OBD II code scanner.
Here’s how:
The most common reason a modern vehicle’s spark plug wears out is the wearing down of the electrode (normal wear), followed by carbon deposits. Consult the chart below to help you determine why your Altima’s spark plug went bad.
Be aware that almost all symptoms of a bad spark plug in your Altima could also be other issues with the ignition system. Good luck diagnosing the problem. Feel free to leave a comment below if there is anything that you would like to add.