nobigwoop

I agree that it sounds like classic dirty IACV (idle air control valve) symptoms. I've needed to have mine cleaned every couple of years, since, oh, 80K miles or so (140K now). My Lexus dealer won't clean it -- they'll install a new one for ballpark $400. Ouch! So you'll probably need to use a non-dealer mechanic to get it cleaned. Per other posts, It's not a tough job, and there are Youtube videos that walk you through, but when I tried it I encountered a screw I couldn remove, so now I just have a local shop do it.

I've had good luck with Meguiar's PlastX plastic cleaner & polish. At $10-ish for 10 fl oz, it was overpriced, as are all Meguiar's products, but it does a great job, and one bottle lasts forever. No kit, no multi-step process, no motorized polisher. Just clean any dirt off the headlight covers, apply a little PlastX using a clean cotton cloth, rub in for 10 or 15 seconds, let dry for a minute or so, and hand-buff for a few seconds using a cotton terry cloth. Just like waxing, and the product seems to leave a wax-like protective coating. After application, the headlignt covers look like new (140K mi, covers never replaced, car lives in dusty Baja). I've been using it a couple of times a year for several years, and have noticed no problems associated with its use.

"Oh drat! Just got a call from my wife. " I have a 2000 Rx300 with 96K miles. Though clunking and loss of reverse sounds like transmission problem, stalling at stop lights sounds like a dirty idle air control valve, another very common problem on this vehicle. It's straightforward to clean it, but it's a little beyond what the person who just does oil changes will probably want to get into. Dealers won't clean it; they want you to buy new one for $400+ bucks. Contact your local reliable independent shop. There's plenty of discussion on the internet about Rx300 transmission problems. I'd just add a couple of things. Consumer Reports surveys show transmission problems in this vehicle as being "average", which is a little worse than what we'd hope for a Toyota product, but not indicative of a dismal situation, as internet reading would have you believe. On the other hand, if it happens to you, of course it's dismal . If the vehicle isn't dead, and you want to find out more, I highly recommend sending a sample of your used ATF to Blackstone Labs (http://www.blackstone-labs.com/index.html). They were reviewed in C & D last fall, and I've had them analyze my ATF a couple of times. Cheap yet comprehensive, and real people do the testing and communicate with you re results. They're happy to engage in some back-and-forth via email, and give their expert opinion :) . If you catch it in time, you can likely extend transmission life through more frequent ATF changes, and making sure the filter screen stays clean. I also recommend buying their pump for taking samples -- very well-made, professional-quality piece of gear that makes grabbing ATF and engine oil samples a snap.