My Michelin tires on my 06 Accord keep losing air on all four tires (front 2 loses air faster) and i cant figure out why. Ive gotten them checked out at costco and everytime they fill them up with Nitrogen (ive tried putting in air as well) it deflates and goes back to 29psi instead of staying at 32psi in the front and 30 in the back. any ideas what the problem is? My tires also have about 1.5 years of tread left

 

Take a tire off the car, spray it with soapy water, & look for bubbles. Don't forget the valve stems. One common thing is corrosion around the lip where rubber meets the metal wheel.

 

Check for cracks in the tire sidewall. Also check the rim lip for rust and dirt that could prevent a proper seal. Also check the tire valve for air leaks.