(SOLVED) Dead cylinder at idle? Low temp on header collector

Swapped the intake for a fresh blue painted one. Wonder if I need to plug the hole in the floor? People say no need to plug, but I left the upper plane threaded hole unplugged and those 4 cylinders were running like dog **** until I plugged it. Lower plane hole is still wide open.
Is there an EGR valve on the manifold? If yes is the valve leaking or stuck open? Is there vacuum going to it at idle?