I just changed sensors on my transmission the easy access sensor had build up of metal shavings on it again after being cleaned last week and my transmission heat light came on as I got home. I bought some more ATFIV for Sundays service. I will change both oil and transmission fluid on Sunday but will report back tomorrow as driving to work again tomorrow whether the new sensors alone make a difference. I would test drive it but rather have a drink now and relax so will let you all know how tomorrow goes. I am certain I am going to need to change the filter again and probably service these sensors over next few weeks. Tempted to run out and drop oil now but running out of daylight.

 

Talk converter is engaging smooth from start stop so are the gears but not perfect just low revs. I never use the A/C ever I like power.

 

Dropped oil out of transmission and removed filter just now going to let it drip out all night. The magnet was dirty and oil as bad as last week. Oil is burnt and has filings everywhere. Looking more and more like transmission failure all so hot at present so will wait till morning to put it back together.
Had trouble engaging gears on start up. Improvement with sensors less traffic and didn't have much problems with low idle which shall look further into tomorrow.

 

Dropped motor oil today so changed both oil and transmission fluid test drive less shakes on low idle pretty normal going to drive it a week and change transmission fluid again next weekend due to amount of crap i got out of it in one week. Also going to line the pan with magnets next week too. So far huge improvement. I will pull and clean sensors again next weekend and see how it drives this week drive 1.5 hours a day so will see how it feels.

 

if you have the time, please take a pic of the sensor locations when you pull them out. Glad to hear you've gotten a huge improvement thus far.

 

Hello to anyone still on this thread. First time posting on here hope i can be of help to anyone in the future. I have a 2000 RX 300 FWD with 190k miles, bought the car at around 40K miles back in 2004 for $12,000 had it ever since. car has always been garage kept and is in fantastic condition for the age and milage. Lately the car started misfiring very badly. i hooked up my ODBII sensor to it & found what the problem was and it was coming out of cylinder 1 among other codes that were thrown out including a knock sensor 2 Circuit code(P0330), System too lean(P0171), Catalyst System Efficiency Below Threshold(P0420)... to make a long story short let me break it down what I've done to the car since

-Bank 1 & 2 valve cover gaskets (I had a leak in bank 1), spark plugs(All 6) , coil packs( All 6) , both Knock sensors( Bank 1&2) with the wiring harness. New air filter. Oil changed. i cleaned the throttle body and intake manifold .

my misfire was due to a bad coil in cylinder 1 so it threw the code and lexus's are designed to go into a limp mode and i lost overdrive (4th gear) and until i changed the coil i was driving to and from work cruising at 60mph doing 4000 rpm ( you know i was pissed and wanted to fix it right away)

Anyways after i changed the coils and knock sensors i cleared the codes and since then i have had my 4th gear back cruising smoothly at 60 mph doing 2100 rpm like normal.

Everything seemed fine UNTIL i started getting a REALLY bad vibration only at a dead stop and ONLY when in gear (reverse or drive) the moment i put it into park or neutral it completely goes away and idles smoothly. when i put it in drive and I'm at a stop light it vibrates really bad but the moment i lift off the brake and step on the gas it goes away.

I figured it was time to do some work on the transmission (thinking it was a transmission issue) so i had a really good mechanic ive known for years and trust, change the tranny fluid for me . But the car still vibrates. he mentioned that he hooked up his code reader and said that my catalytic converter is going bad or is already bad ( thats probably all those codes that was thrown out, i haven't done my research on that yet).

After reading the posts up above its not a bad idea to possibly clean out the idle air control valve, that will be my next project. ill check all my motor mounts and see the condition that they are in and if they play any part in this vibration. i will update on my progress.

 

My 2001 RX with 92,000 original miles has been vibrating at idle for the last year or so and seems to be getting worse. I have had two dealers look at it and they are clueless. It it a low frequency drone/resonance that sounds and feels like a large subwoofer booming. I called a large volume Lexus dealer in Atlanta and talked to their service advisor (seemed like a knowledgeable man) and he told me they have no clue how to fix the problem - which I find hard to believe.

Anyways, the car has had all of its service, by Lexus, since new. It runs great on the open road. But when you come to a stop when the engine is warm (and in gear) the bassy drone/vibration appears.

Mounts are good, no air leaks, IAC good, throttle body clean, Oil control valves and screens good, exhaust system good.

I do notice that the vibration is much much worse with the AC on. I have a VW Golf R that is supposed to have a boomy exhaust note. My RX now sounds like the Golf, except it shakes more.

I am an engineer and am on a mission to figure this out. There must be a solution. I appreciate your help and ideas everyone. This was my mother's car and I have a sentimental attachment to it.

 

Welcome to Club Lexus.

You have to narrow the possibilities down and the type of problem you state is best diagnosed in person.

Engine, exhaust, suspension, vibrating plates are all possible source of the problem. Mechanics stethoscope and holding with counter pressure should be useful techniques. I would say dont give up and keep searching for a shop who can diagnose it for you.

Salim

 

Has anyone really solved this problem? Sounds like a common root cause.

 

Dude ... we are all eager to help you but you have to narrow the scope down.

Think rationally about the question you are asking.

My wild guess says have the Pre-Cat WU looked at, This is the piece that is directly before the flex coupling. There can be crack inside the heat shield. What is the chance of me being right? Less than 0.01%,

Salim

 

Hi Salim,

Thanks for the help. Is the crack inside the heat shield easy to see? Doesn't sound like a common problem if you are giving it a 0.01% probability. What are the high probability components for the symptoms I described?

Thanks for the help.

Rich

 

visit a muffler shop and have the exhaust eliminated.

Salim

 

Hey everyone , glad to see people are still on this thread. @RX300FUN i believe i have found a solution to this vibration problem we are experiencing. As i stated before when i would put the RX in park or neutral the car would idle nicely , calm smooth. But as soon as i put it into drive or reverse the My RX would immediately start to vibrate very hard, at stop lights, in parking lots, etc.. Anyways i have a client who is a mechanic and i asked him if he could take a moment and check out my car, he gladly said yes. We opened the hood and started the car, then he asked me to put the car in drive, hold down the brake pedal and also press down on the accelerator at the same time. The problem became obvious in a matter of 2 seconds. THE MOTOR MOUNTS!!! My engine lifted up several inches into the air when the engine was accelerated while the brake was held down. Again i tried in reverse and the same issue happen, my entire engine moved greatly. I am very certain my motor mounts are the issue to this vibration problem at idle. Im going to order all new mounts, replace them and give an update. I suggest you try this same test i performed with a friend of yours to check if this could also be your problem. i realize you said your mounts are good, but how certain are you of that? did you recently replace all you mounts? anyways its a quick and simple test that i think can shed a lot of light upon this problem. Make sure you have a buddy with you when performing this test (one in the car, one looking at the engine) .


By the way i did also clean the idle air control valve as i mentioned in my previous post that i would do. i could tell the upon startup the car breathed much better. It started up much faster in my opinion and it was a fairly easy job to do, i think anyone with high milage should definitely do this cleaning whenever they have a chance.

 

Jaycee22, please keep me apprised of how your RX runs after the mounts are replaced. I am skeptical but hopeful for you. I did power brake my RX and saw very little, if any movement, from my engine. I did this several weeks ago, by myself and then also at the dealer. I changed my dog bone mount just to see if I could change the resonance. It changed nothing, and the old dog bone mount was in excellent condition.

 

New mounts new transmission fully rebuild and few gear new talk converter and finally fixed mine.