Down a cylinder or misfiring badly

Hi,

Many different things can cause a misfire. By chance, have you scanned the computer to determine which cylinder is causing the issue? If you have and replaced ignition components, the next thing to do would be to check engine compression. That would tell you if you have a weak cylinder. Also, it could be a fuel injector not working as well.

First, here is a link that explains how to test engine compression. Take a look through it. If you don't have a compression gauge, most parts stores will lend one to you.

https://www.2carpros.com/articles/how-to-test-engine-compression

When checking, the lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than (100 psi). Perform compression test with the engine at normal operating temperature, spark plugs removed, and throttle wide open.

Let me know what you find or if you have other questions.

Take care,
Joe