Check engine light on and terrible MPG

1997 JAGUAR XJ6
103,400 MILES • 4.0L • 6 CYL • 2WD • AUTOMATIC
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GILONNI DEAN-CURRERE
  • MEMBER
  • 1 POST
After filling the car with regular and adding both fuel cleaner and off-brand octane-boost Check Engine lit up and started heavy fuel consumption.
May 16, 2022 at 11:40 AM
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SQM
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 6,383 POSTS
Hello,

This issue could be due to a number of components.
Since the check engine light is illuminated, a good first step would be to scan and retrieve the trouble code(s). That can help in determining what the issue is.
If you do not have access to one, most auto parts stores have scanners that can be used to get the codes.

Here is a helpful guide:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Find out the codes and let me know what they are or if you have any questions.

Thank you.
May 16, 2022 at 4:28 PM
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