1997 Dodge Ram 1500 5.2L 4x4 fuel problem

My truck has been giving me some problems lately. I think it may be something to do with the fuel. It usually happens when I drive far distances. If the speed changes say like from 60mph to 45mph, the truck starts bogging and makes putting noises, it starts to slow down and when I push on the gas pedal, nothing happens. I have to pull on the side of the road, turn of the truck, turn it back on, rev the engine a bit, then sometimes it goes back to normal and sometimes it continues until it finally backfires. It also happens sometimes when the gas is half full.I took it to get a diagnostic test and it came back fine. The mechanics were kind of mind boggled because everything seemed to be fine. Could it be a clogged fuel line or the filter or is it something mechanical? I also just changed my spark plugs and lines and tried to put in fuel injector cleanser. I have to change my ball joints and suspension soon, could that add to the problem. Please help me someone! You could connect a fuel pressure gauge to the rail and watch the pressure when the problem is occurring. If you have a fuel pressure related issue, you'll be able to tell by watching the gauge.