If your tags are firing multiple times then your targeting criteria is most likely incorrect within Google Tag Manager. For example, your add to cart conversion pixel may be firing on a product purchase conversion success page where your conversion pixel is firing.
You will need to create what are called Exceptions within Google Tag Manager and add a exception targeting to an existing tag. For instance, a add to cart conversion pixel which is firing on a conversion success page you would need to create an Exception Trigger which prevents the pixel from firing on the incorrect page.
In addition, if pixels are being fired multiple times, you may have tags firing both from Google Tag Manager and directly from the webpage’s source HTML. Merely remove the source HTML FuelX conversion pixel tag and your issues should be resolved.