Ironman infinite help!

Ok i’m just startin to use ironman and i can sorta do his lp, lp, lk, hp infinite but the cpu keeps fallin out of the combo. Can anybody help me figure a way to keep them in the air.

The rythim is( lp, lp,—lk,—up+hp) you pause for a brief moment after the second lp and after the lk.

im havin problem to i havent got to this yet but i was also wondering do i need the game to be on level 99