How To Test A Misfire Problem (2004-2008 3.5L Malibu)

Testing a misfire condition that's lighting up the check engine light, with a misfire trouble code, can seem like a daunting challenge on the 3.5L Chevy Malibu.

The cool thing is that there's a specific diagnostic flow to testing a misfire condition (yup, there's a ‘method to the madness’ of testing a misfire condition).

In this tutorial, I'll explain some of the basics of testing a misfire condition that'll help you get to the bottom of the issue.

Symptoms Of A Misfire Condition

You're going to see two very specific things when your 3.5L Chevrolet Malibu is suffering a misfire condition.

The first one is the check engine light shining nice and bright on your Chevy Malibu's instrument panel. And it'll be shining nice and bright because of one or more of the following misfire trouble codes:

• P0300: Random Cylinder Misfire.
• P0301: Cylinder #1 Misfire.
• P0302: Cylinder #2 Misfire.
• P0303: Cylinder #3 Misfire.
• P0304: Cylinder #4 Misfire.
• P0305: Cylinder #5 Misfire.
• P0306: Cylinder #6 Misfire.

The other thing that you're gonna' see that your Chevy Malibu's engine will idle rough. You'll also see one or more of the following:

• The engine misses when you accelerate the vehicle down the road.
• The check engine light flashes when the misfire condition is present.
• The exhaust smells of raw gasoline.
• Bad gas mileage.

What Causes A Misfire Condition

The 3.5L V6 engine in your Chevy Malibu has 6 cylinders. Each cylinder needs air (compression), fuel, and spark to produce power.

So in a nutshell, a cylinder will misfire because it's missing either compression, or missing fuel, or missing spark.

On the 3.5L V6 Chevy Malibu, the most common cause of a cylinder misfire is a problem with the ignition system. To be a bit more specific, the following components will cause a misfire condition when they fail:

• A defective spark plug wire or wires.
• A bad ignition coil.
• A bad spark plug.

Of course the ignition system isn't the only system that can cause a misfire problem. The other components that can cause a misfire, when they fail, are:

• A bad fuel injector.
• A clogged fuel injector.
• A cylinder with low compression.
• A bad intake manifold gasket leaking vacuum.

The cool thing is that pinpointing the exact cause of the misfire boils down to doing a few specific tests. And that's what I'll discuss in detail in this tutorial.

What Tools Do I Need?

You'll need a few tools to be able to test a misfire condition. The cool thing is that the tools you'll be needing and using are not going to break the bank.

The basic misfire troubleshooting tools you'll need are:

• A spark tester.
• An engine compression tester.
• A multimeter.

You can borrow or buy most of these tools at your local auto parts store.

STEP 1: Find The Dead Cylinder First

The most important first step, when diagnosing a misfire condition on your 3.5L Chevy Malibu, is to find the cylinder that is misfiring.

This is probably the easiest part of the whole process because you can easily identify the misfiring cylinder by simply connecting a scanner or trouble code reader and checking for misfire diagnostic trouble codes.

Once you've got the misfire trouble code, you can use the above illustration to identify the cylinder on the engine itself.

Now in some cases, even though the engine is suffering a bonafide misfire the fuel injection computer will not set a misfire trouble code. In these cases you'll need to do a manual cylinder balance test. You can find this test explained in detail here: How To Do A Cylinder Balance Test (2004-2008 3.5L Malibu).

Once the the 'dead' cylinder has been identified, the next step is: STEP 2: Making Sure The Dead Cylinder Is Getting Spark.