1989 F-150 V8, Fuel Injection, Dual Gas tanks, not getting the gas to start?

Don't drive it much, but the front gas tank has been reading full too long. Was running great, but the last few times I used it, it's been running rougher and rougher, like the gas was getting too old. When it ran real rough, brought it home quick, it died and won't start now. It's not getting the gas. Electrical is fine. At the end of trying to start it I do get "the buzz" sound. I changed the fuel filter and nothing. Man, I miss carburetors -- I had more control. Can't take it to the mechanic-- spent enough already getting somethings fixed and putting it up for sale. I need a plan of attack or my husband is going to junk it. It's a good truck with only 87,000 miles on it. Help!