Trigger mods will cause that. If not modded, it could be the contacts for the thrust trigger on your controller. To check, switch controller to left handed such that the thrust trigger is switched and see if it works normally; if it does, then the problem is likely your controller (some people have said they took them apart and cleaned the trigger contacts to correct this, but I have never done that, so take it for what it's worth!) Good Luck Guardian!

are you using a controller with hair triggers? if so turn it off when on a sparow.