I have a 2021 Coleman 400utv with 60 miles on it. I bought as project. It’s idled ruff and fouled plugs since it was new. I have removed and cleaned throttle body new injector new idle air valve new oxygen sensor. Installed ngk iridium plug. Starts and run good for about 5 or 6 miles and fouls plug. It runs rich all the time. I’ve done reset on ecu. I’m about to think it’s time to try a new ecu. Anyone please help.