Thanks for the opportunity to post here, this is my first post. We have a 2000 Suz DT60 with 1100 hours and a good history, good compression. It starts fine and handles lower idle speeds, but then runs rough between 2000-3000 rpms, and will not exceed 3000 rpms unless in reverse, where it seems to run normal or at least the tach will go to 4000 rpm (which sounds weird). We've replaced the plugs, injectors, low pressure fuel pump, fuel filters. We've inspected the fuel tank, fuel vent on tank, fuel line leaving the tank and the uptake screen on tank line. After running yesterday for an hour at 2000 rpm, the plugs had some excess gas on them, which then made me think it was getting fuel, just not handling properly. Wondering if the fuel vapor separator, which I know next to nothing about, is a likely place to look. Also, wondering if there are some sensors that might be impacting. We have check the neutral over-idle sensor for mechanical function, have not checked it for continuity. It is does not appear to stick. I appreciate any thoughts you might have.