Every time I go to change my oil I'm missing another lugnut on the passenger side. I've gone from 5 down to 3. Thank god I only work a 1/2 mile away. I know its not safe but any ideas about what could be causing this to happen.

When you loose a lugnut, are you breaking off the stud? (I.e., is the lugnut just unscrewing or is the stud shearing off?)

It can be as simple as the person who last worked on that wheel didn't torque them (lugnuts unscrewing) or did 'em with an impact wrench and over-torqued them (shearing off the studs.

If you have to replace broken off studs, pick up a dozen and do all five on the hub at once (hold the rest in reserve for the other side) With a mallet and a big punch you can drive the old studs back out of the hub. There'* a notch in the spindle just for the purpose of allowing a stud to be removed and installed on the hub without dissassembling the entire axle...just rotate the hub around until the head of the stud is over the notch and drive the sucker out.

Oh, pick up some anti-sieze paste when you get replacement lugnuts/studs and apply it to the threads of the studs before you put the lugnuts back on. Makes it much easier to work with later on.

Yeah they are just chearing right off. Could it be that someone cross threaded them when they worked on the car last?

Oh and I would not drive it if all 3 lugs were in line but there are 2 on one side and the other single lug is directly across so its a triangle and it doesn't vibrate....yet :P

You need to fix that ASAP. Advance has a box of ten for $12.00. Singles are $1.50 to $2.00. Are they rusty?

The two that sheared off seem rusty so when I get paid I am replacing them all and then checking the other tires for similar problems.

A small dab of grease or Never-Seez will help prevent the threads from rusting.
PB Blaster will help free up any others that are rusted.