Jeep P0303 – Engine Code Solution – Third Cylinder Misfire

What does the Jeep code P0303 mean?

If you experience a Jeep engine code P0303, the third cylinder of your car is misfiring. You will often get this code alongside code P0300 that signals trouble in one or more cylinders.

There is good news and bad news here. If you only see the code P0303 (or the P0300 alongside P0303 alone), you only have to worry about one cylinder. That’s a great thing! As long as you compare it with the possibility of having to deal with more than one misfiring cylinder, that is.

Jeep Code P0303

  • Cylinder Misfire Fault Detected

Symptoms of code P0303

  • Engine light is on
  • Shaky engine
  • Lack of power
  • Jerky acceleration

Causes of code P0303

  • Faulty or worn out spark plugs
  • Faulty ignition coil
  • Poor quality fuel
  • Broken/clogged fuel injector

Fixes for code P0303

  • Replacing the spark plugs
  • Replacing the ignition coil
  • Replacing fuel injector or injectors

Unfortunately, one faulty cylinder is bad enough for you to stop driving.

Your cylinder is in charge of a lot of things (and all of them are engine-related). If one starts messing up, you could end up with a broken engine.

In all honesty, it can only get worst from here if you keep driving.

On the plus side, a cylinder giving up on you is not the end of the world! You’ll probably have to pay for a spark plug replacement and carry on with your day right after.

Try not to drive with the code P0303.

You may break your engine before you finish driving.

You could also crash before as well since cylinders are in charge of engine power and car control (and a faulty cylinder could take that away from you).

In this scenario, I highly recommend calling a tow truck if you’re far from home.

Can I drive with a code P0303?

Absolutely not! Driving with a code P0303 (Or any related codes, like P0300, P0301, P0302, etc.) should be out of the question. Using your car when a cylinder misfire is a recipe for disaster – and not an option if you don’t like to put your car at risk.

Let’s put it this way: your cylinders are in charge of generating combustion. That means they are the ones that take fuel and turn it into power.

When a cylinder misfires, the (necessary) combustion process starts to fail. Your engine loses power and so does the rest of your car.

Needless to say, combustion is, quite literally, an explosion (If you never thought about it, cars are explosion-powered machines. Yes, they are that cool.

And you don’t want the thing in charge of creating these explosions to malfunction while you’re using it.

In the end, driving around with a misfiring cylinder ends in engine failure. And that costs a lot more than waiting for a bit and fixing the issue.

What could cause a cylinder to misfire?

More often than not, a faulty spark plug, clogged or broken injector, or a damaged ignition coil will cause a misfire to happen in one cylinder. In rare cases where two cylinders misfire, the head gasket between them is probably the problem.

Nine times out of ten, there’s something wrong with the spark plug of the misfiring cylinder. On rare occasions, you will have to look at the ignition coil.

And in extremely rare occasions, more than one cylinder will misfire at the same time.

If two adjacent cylinders are involved, it’s the head gasket. If more than that, then you have internal engine failure – that’s a worst-case scenario, though.

Can a cylinder misfire ruin an engine?

You can damage your engine if you drive with a poorly functioning cylinder. You can also put yourself at risk by driving your car like that. When you know you have a misfiring cylinder, the best thing to do is to pull over.

When a cylinder misfires, the engine loses power, and everything else in your car may do the same thing.

So, yes, there’s a big chance a misfiring cylinder ruins your engine – if you continue to drive your car like that.

How much does it cost to replace an injector?

An injector depending on the year of the jeep will range between $80 to $350 each.

Yes, injectors are expensive. Unfortunately, it’s not something that you can postpone or even consider not doing.

Depending on the price per injector, I would seriously replace all of the injectors while you’re already that deep into the engine.

How much does it cost to replace a spark plug?

One spark plug is about $7. Overall replacing your spark plugs is an easy and inexpensive task to complete. Again just like with the injectors, If you plan to do one. Just do them all.

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