If the engine is too rich & lagging power ,your trans won't shift ,however ,you should not run your engine so lean
to make the trans shift ,you need to find the balance of the tune an then the shifting point!
So ,find your tune that your engine is happy with ,then find the adjustment screw on trans then back the screw
up about an 1/8 of the turn ,when you back the screw off ,you are releasing the tension off the shift paw to
allow it to shift sooner!
I have a vid on how to do it!..