Engine hesitation

98 Lincoln Continental 120k V-8

I have a major valve cover gasket leak that will be fixed on Friday.

The car has a hesitation in the engine (like a miss) when going up a hill and just trying to maintain speed.

Could this be a vacuum issue related to the valve cover gasket?

I had 4 coils replace in the past year. Could it this problem be another coil going bad?

Thanks,

Steve