My rear tires (kumho mx) are little more than 1 year old with less than 10k on them. after 1.5 weeks of sitting i noticed one of them was flat. when i went to inflate it at the local gas station it wouldn't go more than 24 psi. 3 days later the tire has lost 2 psi. what could be the issue?

some notes:

while the tire is obviously leaking, the leak is slow; i don't see how this could stop the tire from inflating.

i've used this gas station's pump many times before, so i know it can handle the pressure. my gauge is also working fine.

when i press the tire gauge against the valve, air continually leaks out instead of stopping. faulty valve?

the valve stem cap is damaged (hard to describe how) so this may explain the leak, but not the inflation issue.

when i checked my tires, all the others were over-inflated by ~8 psi due to the heat. could heat be partly responsible?

 

Could be a leaking valve stem. I had this issue with a old civic b/c they were so old.

 

Make a soap/water solution in a squirt bottle. Squirt the valve stem and valve stem core to see if bubbles arise. If they do not, that is not your leak. Check the entire contact patch, then around the tire where it meets the wheel and then the wheel itself. If it's leaking, it will show it's face.

 

^^That. Could be a small sidewall puncture. I just had to replace the drivers side front tire on my Insight due to a very slow leaking sidewall puncture - I filled it up to 32 psi on a Monday and the TPMS came on a week later.

 

great suggestions, I'll try the soapy water. i guess either way i'll have to take it in to the shop. i don't have the ability to patch it at home.

 

If it is in the sidewall you can not patch it.

 

It could be a torn valvestem, those little buggers can be sneaky with their leaks.

 

I had a safety pin jabbed in my tire. slow leak around 3~ per day. get it checked out!

 

Upon further inspection it turned out to be a broken screw in the tread. I could have sworn I heard air leaking from the stem, guess not. Thanks again for the advice.