I have a 2006 Polaris Ranger 500 efi 4x4 and have been dealing with the issue for over 2 years, I can't figure it out. It will start and run fine but will die when you get above half throttle. It will run all day long but will not go above half throttle. I have replaced the fuel pump, TBAP sensor, TBAP sensor harness, TPS sensor, TPS harness, and the MAP sensor harness. Ive tried fuel injector cleaner but it seems to get worse when the engine gets hot. The cooling fan is working properly as well. I'm not loosing any spark from the plug when the engine dies. My only thought now is the injector or the ECU. PLEASE HELP!!

 

I know it's not what you want to hear,but have the Ranger checked out by Digital Wrench. At times cheaper in the long run just paying for an hr shop time in most cases than just throwing parts at one.Like the manual says most of efi problems are wiring related not so much sensors themselves,but and ecu receives all the info from the sensors and has a heck of a job to do. It could be your problem,but no sense throwing more money at it. Let Digital Wrench find the problem or narrow it down.