Working on my RV today, finally got the cowling fixed. Wanted to try a taxi test. The engine (Lycoming O-360 with Rotec TBI) starts really easy, but won't run under about 1500 rpm. I've only run it once before, and that was running way to rich due to my wiring the primer switch backwards. Got that fixed. So, second time running this engine on this plane. Start it up, if the throttle is far enough forward to have 1500-2000 RPM it starts up. Do need to stand on the brakes. Did an ignition test, both the mag and P-mag seem to be working correctly. Seems to respond normally to mixture. Throttle back, about 1500 rpm it starts running rough. Further back (1200-1500) and it just quits completely. Full throttle seems to work fine. I'm not really an engine guy, any ideas for things to check? I could get video of it running if it would help. Do plan on calling Rotec Monday, I have the day off, but it isn't a holiday in Australia.