My garmin watch Fenix 6x pro

Hello 6887658

I am sorry to hear you are having this issue. There are some initial steps to try, if you are having trouble with the GPS speed and distance: 

• Ensure you are using the best GPS settings. Settings that Improve the Distance and Speed Accuracy of the fēnix 6 : 
  • GPS: GPS+GLONASS
  • Auto Pause: Off
  • 3D Speed/Distance: On
  • Data Recording: Every Second
• If you have not recently, sync the watch with Garmin Express to update the satellite location data.
• We recommend allowing for a GPS soak at the beginning of your activities. For this, select the activity and allow this to acquire satellite reception. Then wait an additional 2-3 min. before starting the timer, to ensure you have the best satellite lock possible.