Which race gas running. Oxygenated gases will make run leaner and high octane gases will run richer. Higher octane gas will hurt power if not needed. Races gases wreck the quick disconects fast would try gutting them 1st.
I chased a problem like yours last summer , mine would run fine if you eased into the throttle but if you nailed it it would fall on its face,ended up being a coil. Hope this helps.