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

By: Abraham Torres-Arredondo
Created: 29 October 2018
Updated: 21 March 2024
Articl Id: 852

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STEP 2: Making Sure The Dead Cylinder Is Getting Spark

The ignition system components that are more likely to cause a misfire when they fail are:

Ignition coil pack.
High tension wire (spark plug wire).
Spark plug.

Once you have identified which specific cylinder on your 3.5L Chevrolet Malibu is misfiring (dead), the next step is to find out if it's getting spark.

This can be very easily done by connecting a spark tester to the dead cylinder's high tension wire and checking for spark.

If spark is present, then you can conclude that the high tension wire and the ignition coil are okay and doing their job.

Your next step is to remove the spark plug and visually check it for any kind of damage that could keep it from firing off spark inside the cylinder.

If you get no spark, when you test the high tension wire for spark, then you'll need to test for spark directly on the ignition coil tower the high-tension wire connects to.

If you get spark at the ignition coil tower, then you can conclude that the high tension wire is defective. Now if you don't get spark (at the ignition coil's tower), then you can conclude that the ignition coil is defective.

If the misfire is being caused by a lack of spark, then replacing the component that's causing it will resolve your 3.5L Chevy Malibu's misfire.

NOTE: It's very important that you use a dedicated spark tester to test for spark. Testing for spark by any other means will give you a false test result of that will have you chasing ghosts and spending time and money on parts your Chevy Malibu does not need to solve the problem.

If the dead cylinder is getting is spark, then the next step is to check its fuel injector. Go to: STEP 3: Testing The Dead Cylinder's Fuel Injector.

STEP 3: Testing The Dead Cylinder's Fuel Injector

As mentioned before, if the dead cylinder is not getting fuel then it's going to misfire. And the one component charged with supplying the cylinder with fuel is the fuel injector.

There's a good chance that the fuel injector that supplies fuel to the dead cylinder is underneath the intake manifold plenum. The cool thing is that you don't have to remove it (the plenum) to test it or any of the other fuel injectors.

Testing the fuel injector of the dead cylinder simply involves testing its internal resistance with a multimeter (in Ohms mode).

The purpose of this resistance test is to see if the fuel injector's internal winding has fried. Because if the fuel injector's internal winding has fried then it's not going to inject any fuel.

Testing the fuel injector resistance is very easy to do on the 3.5L Chevrolet Malibu. Depending on the specific year model of your Malibu, take a look at one of the following tutorials:

If the dead cylinder is getting is spark and its fuel injector is OK, then the next step is to check for intake manifold leaks. Go to: STEP 4: Checking For Vacuum Leaks Around Intake Manifold.

STEP 4: Checking For Vacuum Leaks Around Intake Manifold

The intake manifold gaskets on the 3.5L V6 Chevy Malibu are made out of plastic. At around 60,000 miles or so, these plastic gaskets will start to disintegrate.

You'll usually see one of two things if not both when this happens:

Coolant leaking from the ends of the engine where the intake manifold mates to the cylinder heads.
A rough idle condition that lights up the check engine light with a P0300 Random Cylinder Misfire trouble code.

In a nutshell, checking for vacuum leaks involves two simple tests. The first one is visually checking the ends of the intake manifold to see if coolant leaking.

The second test involves spraying carburetor spray on the ends of the intake manifold.

If the intake manifold gasket is bad and is leaking vacuum. Then when you spray starting fluid or carb cleaner around the leak, the engine's idle (RPMs) will change.

This is due to the fact that the carb cleaner will change the air/fuel mixture when it gets sucked into the engine.

When performing this type of vacuum leak test you need to do it with a cold engine (as a safety precaution).

If your 3.5L Chevy Malibu's misfire is not being caused by a lack of spark, or a bad fuel injector, nor vacuum leaks, then the next step is to test the dead cylinder's compression. Go to: STEP 5: Testing The Compression Of The Dead Cylinder.

STEP 5: Testing The Compression Of The Dead Cylinder

Testing the compression of the dead cylinder, when diagnosing a hard to find misfire, is probably one of the most overlooked test when diagnosing a hard to find misfire.

What usually happens, when engine compression is causing a misfire, is that the dead cylinders compression is very low.

The rule of thumb is at any compression value lower than 15% of the highest compression value your engine has will cause a misfire problem.

Although it's recommended that you test the compression of all six cylinders, it really isn't necessary when you're trying to diagnose a misfire problem. Especially if you have already identified of a dead cylinder.

These are the steps I recommend you follow if you have identified the specific cylinder that's dead:

Check the compression of the dead cylinder and one other cylinder that is not misfiring (dad).
Multiply the highest compression number (which is the one you got from the non-dead cylinder) by 0.15.
Subtract the product (of your multiplication problem) from the highest compression number.
The difference from your subtraction problem, is the lowest compression number (value) that the dead cylinder can have. Any number (value) lower than this and the cylinder will misfire.

More 3.5L V6 Chevy Malibu Tutorials

You can find a complete list of 3.5L V6 Chevy Malibu tutorials here: GM 3.5L V6 Index Of Articles.

Here's a list of articles you'll find there:

If this info saved the day, buy me a beer!