So i have a mercury 9.9 4 stroke and recently its started this thing that when i first start the engine it will idle out and run fine until i drive somewhere then on the way down to idle itll run rough then die. And from that point on it will not start and idle unless it idles too low to give it some gas. If i let it sit again itll start again and drive then do the same thing. However if i start it and put it directly into gear and full throttle i can get it to run fine on full throttle but if i come down it will die again. I have no clue what could causing this. Some diagnoses tips and some help into the right direction would go a long way. Thank you 