At first the rear of my 94 would sit all the way down after 3 days or so only when it was cold outside. Never had the problem in the warmer months. Well now even with the warm weather we have had the rear is sagging over night. Come home from work and go out the next morning to see the back end completely down. Fills right back up when the car is started. Is this a leak in both rear bags or could it be something else? How could I tell?

Yes it sounds like you need to order rears, adleast they are cheap. See American Air Suspension. To verify all you need to do is after everything id airred up, as if you are going to drive away open the door and pop the trunck and turn off the air ride switch and wait a day or so. If it is bags leaking you will know.

Time for some new bags.

Yep. You know, rear bags last a looooooot longer than fronts. I have replaced the fronts on my '96 at least three times in the past 10 years. But my rears are still just fine...knock on wood.

If I turn off the air ride it takes a lil longer but still goes down. Well after I get my front suspension done I ill get the rear bags

Don't wait too long as you got a good chance of lunching your compressor by over stressing it.