Why a Blinking Check Engine Light is Bad News

If you have a blinking check engine light on your car’s dashboard, it’s not a good sign!  The blinking light means your engine is probably misfiring and you need to fix it asap.

When your check engine light blinks, it’s a more urgent signal than when your check engine light stays continuously lit.  If you want to learn about what it means when a check engine light stays lit, check out this article. 

Can I drive my car with the check engine light blinking?

Can you? Yes.

Should you? No.

Here’s why… The longer you drive, the more likely you will be to cause more damage to your car.

And since your problem is most likely a misfire, fuel isn’t being properly ignited in your engine. This unspent fuel can pass into the exhaust system where it can (and will!) damage your catalytic converter.

What is a catalytic converter? And why should I worry about damage to it?

Your catalytic converter is basically a filter in your exhaust system. The exhaust from your car passes through it and is transformed to become less toxic before it is expelled into the air.  

There are  all kinds of chemical reactions going on inside of a catalytic converter when exhaust passes through it. If you want to geek out on the science behind how one works, here’s a good article over on the NAPA Know How blog.

Is it expensive to fix a catalytic converter?

Yes. A catalytic converter is a very expensive part because it contains costly metals like platinum and palladium. These metals are part of the chemical reaction that  reduces harmful exhaust emissions. At the time of writing this article, platinum costs about $1,200 per ounce and palladium costs about $2,800 per ounce!

Depending on the make and model of your car, a new catalytic converter can cost between $500 and $2,000.

Do I need to stop driving right away if I have a blinking check engine light?

You should stop your car as soon as you safely can. I’m not a big fan of stopping on a highway or other busy road. So don’t do that. You should get off the next exit and find a safe parking lot to stop in.

But what if I’m just a few miles from home?

If you’re a short distance away from your home, you will likely be OK if you drive your car directly there. 

But if you’re hours away from home, it’s probably best if you just call a tow truck. It would be a good time to use that AAA towing protection you’ve been paying for!

What if my check engine light blinks briefly then shuts off?

It’s a good idea to  have it looked at asap. Different cars behave differently and you don’t want to risk damaging your car. If the light is no longer on or flashing, there’s a good chance the on-board computer system has logged an error code from when it was flashing. Find out what’s going on inside your car and learn if it needs immediate attention.

So why is my engine misfiring?

Generally there’s three reasons why your engine will misfire and make the check engine light flash. Let’s take a look at each reason in order from most common (and least expensive to fix) to least common (and most expensive to fix).

Ignition problem

photo of a spark plug
Spark plugs eventually wear out and need to be replaced. Source: Robert Couse-Baker

This is the most common reason for engine misfires. It can be as simple as a bad spark plug. Spark plugs do wear out and need to be replaced. Replacing spark plugs is a pretty easy job and can generally be completed in about an hour. 

Other possible ignition problems could be a bad spark plug wire or bad ignition coil. As with bad spark plugs, these other problems are fairly easy fixes.

Fuel system problem

photo of a fuel filter
A bad fuel filter can cause an engine misfire. Source: Diego Torres Silvestre

The next reason for an engine misfire is a fuel system problem. Your fuel and air mixture may be wrong.There are a few reasons why this is happening. 

Your fuel injectors might be clogged. Some people suggest using a fuel injector cleaner to fix a clog. But I disagree with this.  I personally don’t think fuel injector cleaner is the fix-all elixir that some people claim it to be. Read more about my thoughts on fuel injector cleaner here.

The other thing you need to keep in mind is that in  order for fuel injector cleaner to work, you’ll need to pour it into a tank of gas and drive your car several hundred miles. And you really shouldn’t be driving your car when the check engine light is flashing.

Other sources of fuel system problems include a clogged fuel filter and a bad fuel pump. These fuel system problems can take a little more time and effort to fix than an ignition problem and therefore will likely cost a bit more to repair.

Compression problems

photo of a blown head gasket
A blown head gasket can cause compression problems. Source: Tony Harrison

Compression problems are the most expensive problems to repair. The compression inside of your cylinders might have a leak. This can cause a misfire. Possible reasons for this happening are a blown head gasket, bad valves, or even a cracked piston…. All problems that will be expensive to repair. But keep in mind, these are less common issues, especially if you’ve been good about properly maintaining your car’s engine.

Can my blinking check engine light be something other than a misfire?

I fact checked several vehicle manufacturers and all the ones I looked at stated that a check engine light flashing usually means a misfire. The car brands I fact checked are: 

  • Chevrolet
  • Honda
  • Dodge
  • Toyota
  • Subaru
  • Audi

Some other car brands may be different. It’s always a good idea to reference your car owner’s manual to find out what a blinking check engine light means in your car.


A blinking check engine light is almost always caused by a misfire. If it happens to you, get your car to a repair shop as soon as possible. If you ignore that little flashing light, you can cause potential damage to your car that could snowball into a several thousand dollar repair job. And nobody wants that. Ever.

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