i cant figure this 1 out ! ive had the tyres checked by the dealers and they say there is no puncture (not even a slow 1),

yet two (yes only two) of my tyres lose pressure..... more when its cold, or if i leave car parked for a WHOLE DAY without driving, then the tyres drop to about 10psi (which means when i make a turn they completely lose all air !!)

BUT when i refill the tyre, (back to 35psi), i can drive it for 200 miles non-stop and it ont lose any pressure??

NOW, heres another thing, my friend has an is200 also, but his is a yr newer to mine. YET HE IS HAVING THE SAME PROBLEM !!

could it be a fault in the alloys?

the guy at the dealers said that alloys can expand and contract in different weather conditions and that the alloys may have become pourous, (ok i can believe that) but y only 2 tyres then if its the alloys? y not all 4?

can any1 help explain whats going on? OR IF ANY1 ELSE IS HAVING A SIMILAR PROBLEM ??

(and if its the alloys, could i get Lexus to replace them (my car is an 02 reg tho so waranty etc is over isnt it)??

not sure if mine is the same problem, but i pumped mine up today and the two rears were 10psi lower, having said that its the first time ive inflated the tyres since i got the car. I shall keep a look out

I've had this problem too
eventually got the tyres reseated and sealed, and all's been well since
it seemed to depend on how the tyre was being pressed when parked.

i have same problem on one rear,possible corosion inside rim.

forget about the pressure loss coming from the rim expanding/contracting, the temperature fluctuations will cause miniscule dimension changes, and the the temperature will still affect the rim if it is rotating or not.

the tyres need to come off so you can have a good look at the tyre bead surface contact area for any corrosion or other roughness