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F18 Afterburner
Found in: Controls Options>Instruments and Systems>Engine Instruments>Toggle Afterburner
Which 320 ?
-If you using the the a32nx that was available in the Market Place last year, remove it as per link. It will remain in you Content Manager & show as uninstalled. Always leave it uninstalled, it’s easy to reinstall by mistake if you select update all.
If that is not the issue, it may be a mod or livery causing problems.