In regards to the blown head gasket if you take off
the oil cap and look on the opposite side of it and
you see a bunch of Milky residue like a chocolate
milk shake but gooey on the inside of the cap that
means you have a blown head gasket. With the
erratic idle that could be your throttle position
sensor that would make your idle go up and down
and play games with the engine's idle. The other
thing could be too is your temp thermostat is bad
the thermostat is worn out and make it overheat.
The oil consumption that could be normal if you
drive those cars 600 miles you usually burn almost
a quart as It gets older or it could be your valve
cover gasket is worn out and it seeps oil over the
engine. In regards to the engine not performing
from a stop and taking off then it sputters it could
be your catalytic converter is clogged and that's
another issue too that makes a car lose power but
check your spark plugs has it had a tune-up lately
hope this helps? And there are additives you can put
in your fuel tank and run the engine at high revs to
clean the catalytic converter if not driving on the
freeway for a certain amount of Miles look online
for the solution on that.