Question about first and second gear

I like to make sure my tunes will also work well for those that drive automatics.
I’m having a hard time getting 1st and 2nd gear to grip and have the automatic transmission switch gears.
It just gutters in the red zone for 3-5 seconds before switching.
I’ve tried making sure my final drive and 1st and 2nd gears are ratios of each other, but still no luck.

Has anyone else experienced this strangeness of guttering out in the red zone?

Automatic trans u need to make sure to run a race clutch

Thanks, I’ll give that a shot.