Need help

Hi guys I purchased a 2009 grizzly 700fi
I can’t keep it running as soon as I get it to start
It shuts right back off I changed the intake air temapture sensor and have also changed the spark plug and put a new fuel pump on it I have also checked the throttle angle sensor and checked out good after I chenged the plug the bike started up and idled until I went to give it gas now it’s back doing the same thing also if I take the air box off and cover the throttle body it will idle sometimes thanks any input would be great