yes, their sucking air, 65;
The year, engine size and if it is the intake manifold or an exhaust manifold gaskets would help.
There are a few gaskets on a car:- Cylinder Head, Water Pump, Inlet Manifold, Exhaust Manifold, Sump Cover,Thermostat Housing,Transmission Sump,Tappet Cover,Valley cover,Side Cover,Sump Plug,Differential Sump Plug, Transmission Sump Plug, Oil Filter, Oil Pump,Fuel Pump, I'm sure there are more but these will get you started Also door gaskets and window gaskets.
the inlet manifold could Be leaking so check the gaskets or the injector seals
it could possibly have either a blown head gasket or intake manifold gaskets leaking
Because it's leaking somewhere. Other than lines in the cooling system, head and intake manifold gaskets are a possibility.
Yes.
what does idle funny mean? Does the whole car shake? (upper engine mount collapsed) Or does the engine shake/misfire? (Intake manifold gasket)
Old spark plugs can make a car misfire, run rough, and not fire at all.
Yes, it could even make it completely ineffective. If it is in a car it can ruin gaskets, seals, or make your car overheat. Which can warp your the pistons in you car.
Contaminated fuel could cause a misfire.
Depending on the cause of the misfire, it could damage the catalytic converter.
Just because a car begins to misfire does not mean the end is near. I means it needs to be serviced.