Started to run rough

2006 CADILLAC CTS
92,000 MILES • 3.8L • 6 CYL • 2WD • AUTOMATIC
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GUSTAVO CUELLO
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  • 1 POST
When in idle is very rough, started smoking black.
Jul 9, 2018 at 1:54 PM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Hi and thanks for using 2CarPros.com.

Based on your description, it sounds like the engine is getting too much fuel. There are several things which can cause this. Also, black smoke is usually the result of a very rich fuel mixture.

The first thing I would recommend checking is the fuel pump pressure and the fuel pressure regulator. Here is a link that will walk you through the process:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Lets start with that test first. I have attached a picture of what the fuel pressure should be.

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

Take care,
Joe
Jul 11, 2018 at 8:10 PM