Fuel Pump issues?

[rycb20]

I have an 02 emc envoy. The problem I am having is, when i get up around 70mph my truck starts putting and poping and slows down, and its like it doesnt have any power, but it doesnt stall out. But i step on the gas and go nowhere, im limited to about 15mph or 10mph almost idle speed. Once I turn it off and let it sit for awhile its fine again. I have changed out my fuel filter thinking it could be clogged, and that didnt help. So I am thinking it could be the fuel pump. Has anyone had this problem or do they know what it could be? My check engine light was on and I hooked it up to the computer, and it said the engine was running to rich and to lean. If you can help id appreciate it.