artbuc

My 99 RX is idling too fast and too long. I keep it in an unheated garage which may drop to 40-45 degrees on a cold night. When I start it, it idles at 1800 and doesn't come all the way down until I drive it a few miles and the engine comes up to normal temp. At that point all is well. Any tips on what to check first? Seems like it could be the IACV or the engine temp sensor.

Do a search on this RX300 forum using keyword "sparkplug". Thread will give some info and link to ClubLexus which has a very good, detailed explanation. Good-luck.

My 99 rx has 60k miles. Have changed ATF every 15-17k miles. Since reading this forum, thought I better start changing every 10k. Until now, ATF coming out of both drains looked pretty good. This time however, ATF coming out of main pan (about 4 qts) looked slightly dark red but not bad. ATF coming out of housing drain (about 1 qt) was nasty- noticeably darker and the end of the drain plug was covered with a black sludge. Why would the fluid look so different? I assumed the ATF would be well mixed and look the same from both drain locations. Doesn't sound good to me. Any suggestions? I think I'll do another drain at 5k and see how things look.

SK, where and how should I add the Seafoam? Seafoam suggests pouring it slowly into a vacuum line such as the brake booster line. I can do this but I wondered if there is a best way to do this on the RX. Maybe it really doesn't matter how I do it as long as I follow the basic instructions on the can?

My 99 RX is approaching 60k miles and I want to clean air intake with Seafoam as has been recommended on this message board. The instructions on the can give a couple of ways to add. Is there a best way to add Seafoam on the RX? If so, what is it? I was thinking of doing this: removing air supply boot from throttle body, putting the Seafoam in a spray bottle and spraying it right into the throttle body. This seems like a btter way than just pouring it into a vacuum line.

That explains why rear pads cover only 75% of the frictional surface, leaving 1/3 to 1/2 inches of rust ring. It is fine to use common part among models but Toyota must know SUV needs bigger brakes since it is heavier with higher payload limit. Rear rotor is already tiny and not vented, I am just puzzled why anyone would use the brake pad designed for a compact sedan to ghetto fit a SUV :chairshot: ← Are you saying Toyota's rear brake design is bad on the RX300? I believe this is possible because the rear pads are showing almost the same wear as the front pads. On my Avalon, the front pads were shot at 60k while the rear pads look like they can go another 50-60k. My RX front pads are shot at 60k and the rear pads look like they only have another 5-10k on them. The front pads for the 99 Avalon and 99 RX300 appear to be identical. It doesn't make any difference whether you buy them from Toyota or Lexus. If this isn't true, I hope someone tells me. Based on aftermarket stock numbers, it appears that the rear pads on the RX300 are identical to the rear pads on a 99 Celica. I have yet to confirm this. Is it possible that the dimensions of the pads are identical allowing aftermarket suppliers to specify the same pads for the RX and Celica, but Toyota uses one pad material for the Celica and a different pad material for the RX? I am not interested in putting cheap parts on my vehicles. On the other hand, I am not interested in paying Lexus $15 more for the exact same pads I can buy from Toyota.

Lenore, not sure about Type C but I used Mobil 1 75w-90 synthetic to change out my front and rear differentials. Cost me a little over $8 at Autozone. BTW, the front drain plug is a pain to remove, be very patient since there is not enough space to fit two "claws" on my Craftsman 15/16 open ended wrench. You can easily strip the soft alloy plug, I just angle the wrench until I get a good grip. ← Any problem with the Mobil synthetic mixing with residual (undrained) gear oil? Any special flushing/decontamination required before adding the Mobil synthetic?

Toyota pads are good. There is a TSB on RX OEM pads clicking and clunking when you shift from D to R. However, not all cars have this problem. See multiple discussions on this problem on RX300, RX330 and even ES http://www.clublexus.com/forums/showthread.php?t=128059 http://www.clublexus.com/forums/showthread.php?t=154152 I hope you don't run into this problem. Like Mikey00 said, you must tell your mechanic to re-use removable wear indicators if you don't DIY. A lot people who install themselves have to go back and install them since this is not a common design. Good luck ← I have not had the brake click when reversing direction on my RX. However, I had it big time on my 95 LS400 and 99 Avalon. I had the LS400 in the lexus shop several times and they said my brakes had a design problem and could not be fixed. I didn't believe them until I bought the Avalon and ran into the same problem. Yes, I did reuse the indicators. Also lubed the slide pins and re-lubed the back shims. Looks like the rear pads on the 99 RX are identical to the 99 Celica.

Ok, the deed is done. Got new Toyota front brake pads for my 99 RX at local Toyota dealer for $46.78. Same pads from Lexus dealer are $62. Toyota part number is 04465-33121. Now I begin the search for Toyota part number for rear 99 RX pads.

According to aftermarket stock numbers, it looks like front brakes on 99 RX are the same as 99 Toyota Avalon. Any problem with getting Avalon brake pads from Toyota dealer and putting them on my RX? Toyota dealer is closer and cheaper. Braking on my Avalon stinks so I replaced front original pads with Hawk Pro Ceramic. Braking is dramatically improved but my front wheels are black after just 1500 miles. Since braking has always been good on my RX, thought I would stick with Toyota pads.

Well, ok. That tells us that a lot of fluid is trapped in the torque converter and can't simply be drained from the two plugs underneath. Mixing old, burnt fluid with new fluid is not proper maintenance. It would be comparable to draining half of the engine oil out every time you performed an oil change. ← Here is the approach I use. Buy 25 qts of Type IV ATF. Drain and refill every week (or every other week) for 5 weeks. At the end of this campaign, you will have replaced 98% of the ATF. Yes, it takes some time. But, it is a relatively cheap and easy way to flush your system. If you back off to three changes instead of five, you will replace about 89%.

Bluestu, could you describe your flushing procedure? I have been draining & refilling removing both drain plugs and replacing about 5 qts. Do you think this is good enough?

Searching this forum I have found several cases where people get noticeable improvement after cleaning the throttle plates on their RX's. Out of curiosity, why would a dirty throttle plate have such a big effect on engine performance? If the throttle bodies were partially blocked with crud I could understand getting a big improvement, but big improvement by cleaning the plate? Why are the RX engines so sensitive to minor build-up on the throttle plates?

Steven, I'm getting ready to check-out the TB sensor on my 99 RX. My shop manual gives the following instructions for installation: With throttle valve fully open, insert the TB sensor to the throttle body with it turned clockwise by 30 to 60 degrees against the fully-open valve position. Then, torque the sensor by turning it counterclockwise. Did you follow this rotating/torque procedure? I assume you have to do this to make sure sensor does not bottom-out at full throttle. Finally, can you give me the Toyota part number for the sensor? Thanks.

wwest, yes I am a little older. 56 to be exact. I am a retired engineer who loves to tinker so it doesn't take very much encouragement for me to tear into anything. I am brand new to this forum and I want to thank-you very much for taking the time to give me such a thoughtful and complete response. Most people think I'm nuts about car maintenance, especially when I tell them I replace brake fluid every two years. But, guess what? I usually drive my cars 150-175 k and I have never had a caliper failure.

Isrlex, the IACV is right under the No.1 Throttle Body (closest to the firewall). I haven't worked on mine yet, but I would say the easiest way to remove the IACV would be to first remove the Throttle Body itself. Pretty straightforward job although it does involve disconnecting a couple coolant hoses. You can find motorvac info at www.motorvac.com. If this looks too expensive/elaborate for you or you can't find a nearby dealer, other posters said they just used a throttle body cleaner and toothbrush. This is what I plan to do. I just removed my MAF expecting to find it dirty but it was clean as a whistle. So, I'm not in a rush to clean the IACV and/or Throttle Body.

Ok. I've done my homework as I should have before I made my first post. I now know what motorvac is; how to clean my MAF, IAC and TB; how to change the back spark plugs; the many causes for RX300 hesitation; pros/cons of K&N filters and how to modify the cold air intake. All great stuff! I was not able to find the answers to my fuel filter questions. I did find a couple expert opinions which said my fuel filter almost never needs to be changed so maybe I should just chill on that one and not worry about replacing it at 58K as preventative maintenance. However, if someone has replaced their 1999 RX300 fuel filter, please let me know if you have any installation tips. Thanks.

Wow! Just discovered this site and I'm luvin' it! Regarding my 99 RX300 AWD w/ 58K miles: 1. This forum indicates chronic problem with carbon in intake manifold. What is the best procedure to clean? SK perf says "motorvac" but I am not familiar with that term. 2. Is there a way to replace rear spark plugs without removing intake manifold? 3. I like to change fuel filters at 60k but that job looks like a mess according to my shop manual. Shop manual also says certain parts are not re-usable, eg mounting gasket and o-rings. If I do this job, should I follow shop manual or attempt to re-use gaskets and 0-rings? Can I buy an aftermarket filter or should I buy Lexus? Do I need to replace fuel pump inlet filter while I'm in there? This car has been fine except for slight hesitation when first pressing down on accelerator.