Oldsmobile/Buick Repair: 92 olds CS not starting, olds cutlass supreme, olds cutlass

Question
I have a 92 Olds Cutlass Supreme S with a 3.1L V6, approx 118K miles.  In October, I began having problems with it starting. It would start if I jumped it, but it seemed as though something was draining the battery.
Here's what I've done:
New battery(twice)
New alternator
New TPS
General diagnostic
several parasitic drain tests
new positive battery cable
tested starter

I've had this car in the mechanic 4 times and they STILL can't figure out what was wrong with it.  I can't afford to take it to an electrical shop.  Any ideas?  Any help would be GREATLY appreciated!

Thanks!  

Answer
Hello Melissa,
If it is really draining the battery every night, a parasitic drain test has got to be able to find it.
Have you tried disconnecting the battery at night, and seeing if it would start in the morning then?

Trunk light, glove compartment light, etc need to be checked.

If the battery is acting low, it might not really be low, but a bad ignition switch, or a bad starter solenoid could be the cause. Measure the battery voltage with a meter.

Van