I would start with your battery.
Yes it will.
When vacuuming a pool manually a loss of pressure can be caused by something getting stuck in the hose. A leaf or a large bug can get stuck in the hose and cause it to lose pressure.
Cold can cause loss of preassure, so the patriots probably didn't cheat
worn crankshaft bearings
It will not cause low water pressure. It will cause a loss of heated water because the heater will not be able to recover fast enough. It has nothing to do with pressure.
It's possible, but much more likely there is a leak somewhere.
No.
It could simply be a bad catalytic converter. I have seen this cause a lack of oil pressure. Have a mechanic check it, or if you don't care, chop it off with a sawzall and see if it runs.
Did you check for compression loss? or Is the catalytic convertor blocked?
Usually, a loss of pressure in your brake system means that there is a hole somewhere in the system. A leaking brake line or a punctured reservoir could cause a loss of pressure. A bad master cylinder could also cause a loss of pressure in the back brakes.
The simplest answer would be that the screen in the spout is clogged.