1995 Taurus Engine cuts out

Does the service engine light come on? If it does, you need to get the computer scanned for trouble codes. To answer your question, the idle speed is not adjustable. The computer controls that. There are no adjustments on the AC clutch either. Just to clarify, the car only stalls when stopped and you take it out of gear. And only when the AC, or defroster is on. Otherwise it doesn't stall with the AC or defroster off. You might want to check for proper routing of the serpentine belt. It's on a sticker under the hood. You also should check for proper voltage from the alternator. Using a digital multimeter, you can buy a cheap one for $10 at walmart, set it to DC volts. With the car running and no lights or accessories on, place the red lead on the positive battery post and the black lead on the negative post. It should read about 13.9 volts. Turn the headlights, radio and blower on. It should still read about the same. I've seen new alternators that were bad out of the box. With the car off check the wiring on the back of the alternator for loose wires. If all of that checks OK, the problem might be the car needs a tune-up, or the idle air control valve might be bad or the EGR valve/system might be bad.

When you turn the ac on, the pcm should compensate for the extra load by increasing slightly the idle rpm, it's possible that this function is not operating correctly. Will the car idle at all with ac on? How about with ac, headlights, fan on high? Maybe the idle control system is faulty? I know on some of the earlier moidels, if you turned the mode switch to ac, then ran a scan with the car not running, it would throw a code indicating that their was a problem with pcm controlling the idle speed, I think the older 2 digit code was 67, yours would be a 3 digit code. Just some thoughts.

If the service engine light isn't on, it's probably not setting a code anyway. You might want to take it to Autozone and have it scanned anyway. Did you check everything lke I asked in the first post? If not, check it to be sure. Also, It may be the idle air control valve. The computer sends a signal to it to keep the idle speed where it should be. Let's check the other things first.

Good for you. Just goes to show you and me to start with the basics. Remember to check all fluids on a weekly basis. When oil is fresh, after an oil change, you may not lose much oil the first 1000 miles. After that, the oil thins some and the leak accelerates.
As for your valve covers, you might want to try snugging the bolts first. You need an inch lb. Torque wrench. They should be torqued to 80-106 inch lbs. Start out at 60 inch lbs. And work your way around the cover and increase to 80 and then to 106. Make sure it's an inch lb. Torque wrench, not a foot lb. Torque wrench. If you can't get a torque wrench, try going around the cover and tightening the bolts a little at a time, about a 1/16th of a turn. Do not force it, the bolts could be snapped easily. The bolts should be good and snug, not very tight. If you want to change them, it doesn't look too hard depending on you skill level. Two things that are important, there are 2 spots on each cover that need RTV sealer. Also, you need to put thread sealer on the bolts. Send me a private message with your e-mail address if you want the procedure and a diagram.

A leak from the oil pan is not unusual for a car with 120,000 miles. It's not a big deal as long as it's not a big leak and you check the oil regularly. You could try snugging the bolts on it too. Just remember to go around 2-3 times and don't overtighten where you could snap a bolt. The oil leaks as you are driving and spreads out across the undreneath of your car. That's why you don't see a puddle underneath your car.