My 2002 polaris 6x6 will start and idle great, but it won't rev up very high in neutral. While driving in high or low it will run great until it reaches over a 1/4 throttle, then it will sputter and struggle to rev higher or pick up more speed. I've eliminated these things as part of what's causing the problem; the airbox, the gas tank, fuel pump, and fule line, the cams and valves, and the carburetor. I need to verify that the correct spark plug is being used, but is there anything else that could be causing this problem?

SOURCE: my new 2008 6x6 sportsman polaris fouls plugs

1) run a hotter sparkplug
2) if it is sitting for long periods of time your fuel could be stale
3) running the wrong fuel
4) worst case. engine is burning oil This can happen if service's was missed from new as oil becomes abrasive causing excessive wear.or motor was defective from new.

SOURCE: 97 Polaris Xplorer 500 4X4 rev problem

REPLACE THE CAMSHAFT !!!,,, HAVE A LOOK AT CAMSHAFT , EXHAUST LOBE IS PROBABLY WORE RIGHT OFF....

SOURCE: 2006 Polaris Ranger 6x6 - AWD quit working; light

You should have a couple wires running to the front differential with a quick connect plug, check this plug to see if it has come apart or the wires were broken somewhere.

SOURCE: 06 polaris rangaer 6x6 700

probably has a bad throttle

SOURCE: I have a 1995 Polaris

i would think so.look in owners manual .