I have a 1990 Escort GT with 161k miles on it that has had a high idle
and battery drain. Basically on these cars if you are not a mechanic
and you don't take it to one you will probably be chasing them down for
a while, so long as the car is driving.
You should probably figure out the stalling issue first before you can
proceed to the high idle situation, unless they are related.
Pull the codes which there are probably some based on what you
described. Otherwise check the pcv valve and plumbing, canp valve, egr
system, vane meter and air hose, all vacuum lines, basically anywhere
unmetered air can get into the system. I had the steel backpressure
line from the exhaust header to vacuum regulator break off, but if you
don't have an exhaust leak you are OK.
Rule out the simple stuff, one-by-one I plugged my pvc intake on the
throttle body, accessory manifold vacuum (except the fuel pressure
regulator, you can test that with a vacuum pump), and egr tap into the
throttle body. If the idle decreases there is probably an air leak in
that part of the engine. If no difference, an air leak is probably
somewhere between the vane meter and the cylinder head. Could be
gaskets, injector o-rings, IAC valve or something else.
The battery drain is from an electrical short somewhere, or a bad
switch. Check the draw with an ammeter from the neg battery post to
neg battery terminal with the car off, it should be less than 100
milliamps, maybe less than 50 not sure. If greater, begin pulling
fuses and look for a drop. This will at least isolate the circuit for
you. The radio and clock always draw from the battery, but this is
supposed to be like 25 ma or so, not sure.
Pull the codes and post them, I can probably interpret them for you
based on my experience with my car.