Ah OK so the mohawk is to transition from forwards to backwards, to link the forwards to the backwards crossovers. Maybe the problem is that you're at this point possibly going quite fast after the crossovers and you don't feel comfortable doing a mohawk at speed. I know that feeling - you get a mental/physical block and the body says no. I would advise practicing it at a really slow speed then building up from there, to gain confidence. Mohawk to backwards at speed is a pretty fundamental building block for a figure skater so it's worth spending time on it to get it right.