Third cylinder is missing and it is running rich?

1998 GMC C1500
305,000 MILES • 4.3L • V6 • 2WD • AUTOMATIC
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BUCKDM
  • MEMBER
  • 1 POST
3rd cylinder is missing and it's running rich?
Oct 6, 2023 at 10:26 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 54,178 POSTS
If you have a misfire the system thinks the engine is running lean so it will increase the fuel input to its max. So, we need to fix the misfire and that part should go away. Let's remove the spark plug for inspection and replace it if needed.

This guide can help:

https://www.2carpros.com/articles/how-to-change-spark-plugs

If that does not help let's do a compression test.

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

This guide can help as well:

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please go over these guides and get back to us.
Oct 6, 2023 at 10:46 AM
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