Sc430 Wheel/tire Leaks Air

[dcjaybird]

I'm desperate for good advice....

My 2002 SC430...only 5 years old...only 35000 miles...has a tire that leaks air ONLY at 55mph or over. I can drive for months and months at city street speed, no problem But, as soon as I hit the freeway, after about 10 miles at 55mph, the tire pressure indicator comes on. And, if I kept going, it would go flat. This is a BRAND NEW tire that I bought to replace the one that had only 10000 miles and was doing the same thing. The rim has also been esamined and cleaned. Yes, we've checked for air leaks, and they just don't show up. The air stops leaking once the tire cools down...and it can't be forced to leak in a tire shop.

It's been to NTB and Merchant's Tire both, in DC. It's been to the dealer Maryland, who's brilliant suggest was nitrogen. Because I've just moved from DC to South Florida, I've also taken it to another dealer in Florida, found nothing.

LEXUS' solution is to take it back to Maryland for further diagnosis. I got an e-mail response the quality of which i would expect from Kia or Yugo or Ford, not Lexus. They're useless, just as they were useless a few years back when I had to replace my runflats. The tires now are good Michelin tires.

Any thoughts? Is there a cheap place to buy a decent wheel? Is it possible that the air pressure sensor is leaking? None of this makes sense...and LEXUS is just making me want to trade the car in on an Infiniti or Mercedes. I absolutely hate it when loyalty is rewarded with a spit in the eye.

[dcfish]

I'm desperate for good advice....

My 2002 SC430...only 5 years old...only 35000 miles...has a tire that leaks air ONLY at 55mph or over. I can drive for months and months at city street speed, no problem But, as soon as I hit the freeway, after about 10 miles at 55mph, the tire pressure indicator comes on. And, if I kept going, it would go flat. This is a BRAND NEW tire that I bought to replace the one that had only 10000 miles and was doing the same thing. The rim has also been esamined and cleaned. Yes, we've checked for air leaks, and they just don't show up. The air stops leaking once the tire cools down...and it can't be forced to leak in a tire shop.

It's been to NTB and Merchant's Tire both, in DC. It's been to the dealer Maryland, who's brilliant suggest was nitrogen. Because I've just moved from DC to South Florida, I've also taken it to another dealer in Florida, found nothing.

LEXUS' solution is to take it back to Maryland for further diagnosis. I got an e-mail response the quality of which i would expect from Kia or Yugo or Ford, not Lexus. They're useless, just as they were useless a few years back when I had to replace my runflats. The tires now are good Michelin tires.

Any thoughts? Is there a cheap place to buy a decent wheel? Is it possible that the air pressure sensor is leaking? None of this makes sense...and LEXUS is just making me want to trade the car in on an Infiniti or Mercedes. I absolutely hate it when loyalty is rewarded with a spit in the eye.

Has the sensor been replaced/checked ?