My rodeo has this problem when I'm driving along all of a sudden it like it looses power and slows down a bit and then it speeds up and back fires a couple of times and then drives normal again

I have owned the rodeo for almost a
year and have replaced different
thing like fuel filter fuel injectors and
different thing now someone said
replace the fuel pump but I thought
when the fuel pump was going out it
had a hard time starting but not my
rodeo it starts right up any ideas how
to fix this