Drivers side losing more tyre pressure

Is the drivers side in the shade when you check?
Do you have a valve stem tool, check the valve stems.

 

Do you park along a curb? Possibly putting more stress on one side?

Seems odd that just one side is low.

 

What side is the sun on when you check them?

 

OK, before checking the pressure, are any tires in the sun?
Had you driven the car for the last 8 hours?
Do you have a teenager in the house?

Have you checked the tightness of the valve stems, a little oil will show bubbles, or soapy water, oil's better, it there are bubbles, take the weight off the wheel, remove the valve stem, lubricate it with oil and re-install it, then recheck it.

 

Could be a small nail, or something similar, a small scrap of metal. We had one tire slowly loosing air, for about 2 years, finally found a slim finishing nail: pulled it and plug repaired.

 

Make sure there's no nail on the tires. Check your tires at the end of the month to see the difference on all 4 tires. If there is tire pressure difference, such as in 20PSI on the right front and rear, and 30PSI on the front left and rear, then your right front and rear tires has a nail somewhere or there is a leak going on. Usually if its leaking really bad, your tire light will turn on in your dashboard.

As in all the comments about parking your vehicle in the sunlight and such, I don't see a difference in that. It is normal for your tires to lose 2PSI every month. I've checked my tires every oil change (which is 6 months or 10k miles) and only see a difference in 4-6psi lost when I check it.