JD CT332 fuel issue

I have a 2002JD CT332 that when I go up an incline or a slant it acts like it runs out of fuel. On flat it does well. Have changed the filter and the water separator and bleed the lines. I can get it going again but the problem reoccurs. I was trying to check the fuel pickup line but it looks like I have to take the alternator and it’s bracket off. Looking for thoughts before I do that