I have a 2012 RZR800, I noticed a lack of top end power. I found it will not go over 5300 RPM, even going down hill full throttle. If i put it in neutral it will go up to 6500 rev limiter, but driving in high will not go above 5300. In reverse it will go up to 6500rpm. In low it hits 5300 then will climb higher about 50 rpm every 3 to 4 seconds. I checked fuel pressure, 45 psi when parked and when driving full throttle. disconnected the exhaust pipe to run open pipe to be sure exhaust is not blocked, 5300 rpm max still and a bit loud.. Pulled injectors , good spray patterns off both. removed air filter no difference. Anyone have any ideas? I am stumped.