1998 Sebring sedan

I have a 1998 Sebring that has a few problems, The vehicle runs (Thank goodness) but it's having some Issues

* Under load (accelerating mostly) there is a high to low pitched whine in the motor/trans (motor I think)

* on the low side of normal Oil pressure,

* right turns w/o accelerations will cause the car to stall

* Random Warning lights come and go briefly

* Leaks oil but no smoke out the back or drops of oil on the ground, heavy cakeing around the filler cap, Burnoff when the car idles after being driven ( I think the leak is somewhere in the top of the motor and it hits the exause manifolds and burns off, Possible Valve cover gasket?

This car my sisters had for about a year, The previous owner let it sit for some time, and the family took it from him and sold it to us, (the were the owners before that, that sold it to her son) and it was a daily driver before it was sold to her son. We've done a full tune up on it... brakes, new battery, new belts.

my main concern is the noise coming from the motor, Last night I checked the oil level and none read on the stick (useless stick anyways, just 2 notches in it) and I added probably 2-3 quarts to get the level between the notches, before that the Whine was incredibly loud, With the oil added it deadend the sound some but not totally, my sister called again and said on the way home from work that it was whineing fairly loud again, I'm worried about the bearings and all the other lower engine workings, I've told her not to drive it anymore pending my exam and the original owners exam (pretty good mechanic) Any suggestions from Y'all would really help me in the right direction on this car..

Thanks

~Josh