Idle Vibration

[bluestu]

Did anyone ever figure out why the RX300 vibrates at RPMs under 8k? Mine seems to only idle rough when in gear and stopped. If I put it in neutral or park the RPMs go up and it seems to idle fine. The low idle causes a low frequency vibration throughout the entire car. It is extremely annoying. Any ideas?

[LexKid630]

Did anyone ever figure out why the RX300 vibrates at RPMs under 8k? Mine seems to only idle rough when in gear and stopped. If I put it in neutral or park the RPMs go up and it seems to idle fine. The low idle causes a low frequency vibration throughout the entire car. It is extremely annoying. Any ideas?

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is the A/C on? Sometimes the air conditioning can make the car vibrate more.

[bluestu]

Anytime the RPMs drop below 8000 there is a low frequency vibration throughout the car, even if the AC is off. The vibration only stops if I put the car in neutral or park.

[2005 GX470]

Anytime the RPMs drop below 8000 there is a low frequency vibration throughout the car, even if the AC is off. The vibration only stops if I put the car in neutral or park.

Is your issue fixed? My 2005 GX470 (64K miles) has the same problem except that the vibration comes and goes without pattern. What is your mileage?

[Karl K]

I had the same thing happen to my 2001 RX 300. I put a can of Sea-foam into a full tank of gas and by the time it was used up the idle was nice and smooth again. Sometimes the fuel injectors get a little cruddy and don't have a good spray pattern and that can give you the rough idle assuming your motor mounts are still nice and flexible.

Hope this helps.

Karl

[NJerseyDan]

I've been having a rough idle just like you guys have described, with my 01' RX300. I performed the cleaning on the IVAC, and just changed my plugs, but it hasn't made a difference. I'm gonna try that Sea-foam stuff tomorrow. I'd always heard that additives weren't very effective. Hope it's not my motor mounts. I hit 100K three months ago. Has anyone changed their mounts or had it done?

[magicgsm]

My 2003 RX300 does the same from the beginning, several mechanics was unable to figure out what causing a vibration. LEXUS dealership saying that it is normal - i don't think so...

Car is under 150K

Of course i tried full tun-up (changing spark plugs, washing engine etc...) no result.

And i figured out that in the winter it vibrates more than on summer...

Is anyone figured out what is the cause?

[SRX]

Did anyone ever figure out why the RX300 vibrates at RPMs under 8k? Mine seems to only idle rough when in gear and stopped. If I put it in neutral or park the RPMs go up and it seems to idle fine. The low idle causes a low frequency vibration throughout the entire car. It is extremely annoying. Any ideas?

My 2000 RX develops a similar pattern to the one you describe after driving it only around town at low speeds with little if any sustained highway driving. If I take the vehicle on the highway and drive an hour or two at highway speeds (65-70 mph), the rough idle is gone after returning to town. Repeat as necessary.

[NJerseyDan]

My 2003 RX300 does the same from the beginning, several mechanics was unable to figure out what causing a vibration. LEXUS dealership saying that it is normal - i don't think so...

Car is under 150K

Of course i tried full tun-up (changing spark plugs, washing engine etc...) no result.

And i figured out that in the winter it vibrates more than on summer...

Is anyone figured out what is the cause?

So I put a full can of Sea-Foam into a full tank, and I've run it 3/4's of the way down. But I still haven't noticed any change on that vibration. I changed my plugs too. Put Bosch4 Fusion's in there. Bosch says they use both Platinum and Iridium. I read a few independent reviews online and mostly everyone says Bosch's claim of 5% better MPG is true. I haven't seen it though. Seems to run the same as before.

Only other thing I could think to change would be the motor mounts. But the vibration is not that bad to justify the time and money.. yet.

[nelliott]

I have a 2002 RX300 w/ 55K miles and experience something similar... to me it seems like a low-frequency harmonic resonance sort of thing. I hear it only while the vehicle is stationary, idling and in gear. Shifting to park or neutral eliminates the noise. There does not seem to be any roughness to the motor, just this low frequency sound resonating in the car.

At first I wondered if it was an exhaust problem, but now I've been wondering if it is related to the transmission somehow? Much more of the transmission internals are engaged while in gear. Clutches, valves, etc are active that are idle when in park. I'm wondering if changing the tranny fluid will make any difference.

I've also found that I cannot hear the noise if I significantly rotate the stereo volume knob in a clockwise direction..

[NJerseyDan]

I'm gonna change my tranny fluid in the next few days. I'll let you know if it helps the vibration.

[code58]

I'm gonna change my tranny fluid in the next few days. I'll let you know if it helps the vibration.

Dan- I can almost guarantee that the vibration is motor mounts or exhaust. The exhaust is often responsible for resonance and vibration noise when a vehicle gets some miles on it. Things loosen up in the Cat. conv. and other exhaust components when spot welds break and other things begin to loosen up as a result of the heat E.S.'s have to deal with today as compared to before smog controls. It's normally not too hard to diagnose. A mechanics stethoscope from Harbor Freight for about $5.-7. is one of the best investments you can make. Motor mounts are also often responsible for that type of noise. A great deal of todays cars have hydraulic mounts (oil filled) and they will sometimes leak the oil out so it's easy to see and sometimes won't leak even though the mount is bad and responsible for the vibration.

[gonowhere]

"I've also found that I cannot hear the noise if I significantly rotate the stereo volume knob in a clockwise direction".

My car does the same. It is 2002 RX300 with 128k. Noise is gone at sligtly higher RPM.

"I can almost guarantee that the vibration is motor mounts or exhaust"

I don't think it is the exhaust. My car has the problem for 5 years already. The exhaust would have been fallen apart.

[pauljcl]

"I've also found that I cannot hear the noise if I significantly rotate the stereo volume knob in a clockwise direction".

My car does the same. It is 2002 RX300 with 128k. Noise is gone at sligtly higher RPM.

"I can almost guarantee that the vibration is motor mounts or exhaust"

I don't think it is the exhaust. My car has the problem for 5 years already. The exhaust would have been fallen apart.

I had the same effect in my 99RX300 since I bought it in 2002. Dealer said it was normal, but if it is anything it is motor mounts which cannot absorb the engine vibration. Coming from a MB, I was astonished that a Lexus would have such an unbalanced idle. Of course, even a slight increase in revs. reduces the felt vibration.

[tmastres]

"I've also found that I cannot hear the noise if I significantly rotate the stereo volume knob in a clockwise direction".

My car does the same. It is 2002 RX300 with 128k. Noise is gone at sligtly higher RPM.

"I can almost guarantee that the vibration is motor mounts or exhaust"

I don't think it is the exhaust. My car has the problem for 5 years already. The exhaust would have been fallen apart.

I had the same effect in my 99RX300 since I bought it in 2002. Dealer said it was normal, but if it is anything it is motor mounts which cannot absorb the engine vibration. Coming from a MB, I was astonished that a Lexus would have such an unbalanced idle. Of course, even a slight increase in revs. reduces the felt vibration.

I have this issue as well and I believe its the motor mounts. I remember this discussion previously and IIRC the RX had some sort of fluid filled MM's that were great initially but tended to fail prematurely and ended up with the low RPM idle (under 1000 rpm) that we all know and don't really love. Usually it disappears when you put the car in N.

[pauljcl]

"I've also found that I cannot hear the noise if I significantly rotate the stereo volume knob in a clockwise direction".

My car does the same. It is 2002 RX300 with 128k. Noise is gone at sligtly higher RPM.

"I can almost guarantee that the vibration is motor mounts or exhaust"

I don't think it is the exhaust. My car has the problem for 5 years already. The exhaust would have been fallen apart.

I had the same effect in my 99RX300 since I bought it in 2002. Dealer said it was normal, but if it is anything it is motor mounts which cannot absorb the engine vibration. Coming from a MB, I was astonished that a Lexus would have such an unbalanced idle. Of course, even a slight increase in revs. reduces the felt vibration.

I have this issue as well and I believe its the motor mounts. I remember this discussion previously and IIRC the RX had some sort of fluid filled MM's that were great initially but tended to fail prematurely and ended up with the low RPM idle (under 1000 rpm) that we all know and don't really love. Usually it disappears when you put the car in N.

Indeed, it does disappear in N, as well as further to any elevation in RPM. I guess the dealer who told me it was normal did not feel like honouring the CPO warranty they said was applicable to the car... or deemed the deterioration of the motor mounts such a 'normal' occurrence that it was not worthy of repair.

[NJerseyDan]

Yeah. I've been scoping out some RX300 Motor mounts on Ebay. Any thoughts out there fellas? Ebay parts okay, or do I need to spend big bucks on the LEXUS Oem motor mounts?

I remember when I first bought the car I would sometimes try starting the car when it was already running, because it was so quiet and smooth. Not No MO!

[teammootracer]

I have the same problem. Its the engine mounts The front one is charged with hydrolic fluid ($$). Im not sure which one is bad, so I'm changing both. I found an aftermarket supplier, 200US for both. Its a 1.3 hr job at the shop, not sure if its worth doing myself, we"ll see. I'll confirm if this fixed the problem after replacing.

[NJerseyDan]

Teammoot,

Where are you getting your mounts from? All the suppliers I've found carry only solid rubber aftermarket mounts.

[teammootracer]

motormounts.net

[NJerseyDan]

Got my mounts and I'm tearing REX apart today. I bought the front Hydro mount from Lexus for $165, the rear motor mount from RockAuto for $40, and the Tranny Mount from Rockauto for $45. Wish me luck fellas.

It's 9pm. I called it quits at 630 when it was too dark to see any more. I got the two motor mounts and one tranny mount in. When I dropped the motor back down i found it was not aligned over the mounts and would not drop all the way down onto them. I hunted for 1 and half hours couldn't find the snag or whats holding up my motor! Anyone have any experiences like this? I must have twisted the motor while prying around to get the old mounts out, but I don't see what it keeping me from twisting it back. A friend suggest the front axles may have pressure behind them. we'll see tomorrow....... ugghh..

Next day. 630pm. well, I did it. It was the engine control mount(think that's what it was in the manual) up on the top passenger side of the motor that was holding my motor out of whack. I loosened it up and the motor practically shifted right into place. I reattached the subframe, tightened all the mounts, and changed my brake pads to ceramics while I had the wheels off. The front hydraulic engine mount was definitely shot. You could see that the diaphragm inside had failed and all the fluid leaked out. The tranny mount was way more compressed than the new one. The rear engine mount looked the same to me, but I put in my new one anyhow. The idle is definitely quieter and smoother now(though not as smooth as I remember..). You still get some of the vibration around 800rpm, but its a definite improvement. Also the car use to make a clunk when I took off from a standstill. Must have been the worn tranny mount, cause it doesn't do it anymore!! Altogether it was an enjoyable project, but plan on doing a lot of cussing, and a lot of prayer to the nut & bolt gods. I couldnt find a write up on how to do this job on an RX, just some writeups on Lexus cars. If theres some interest I'll do a writeup.

[teammootracer]

I would suggest next time only replacing one mount at a time, supporting the engine in place with a jack.

[natesniper8]

Did anyone ever figure out why the RX300 vibrates at RPMs under 8k? Mine seems to only idle rough when in gear and stopped. If I put it in neutral or park the RPMs go up and it seems to idle fine. The low idle causes a low frequency vibration throughout the entire car. It is extremely annoying. Any ideas?

My 2000 RX develops a similar pattern to the one you describe after driving it only around town at low speeds with little if any sustained highway driving. If I take the vehicle on the highway and drive an hour or two at highway speeds (65-70 mph), the rough idle is gone after returning to town. Repeat as necessary.

HEY SRX! I have had the same exact problem as you this last couple weeks. Mine also goes away when I hit 65-70.. Did you ever end up figuring out what the cause was or were ever able to make that go away??

[trankie]

Did anyone ever figure out why the RX300 vibrates at RPMs under 8k? Mine seems to only idle rough when in gear and stopped. If I put it in neutral or park the RPMs go up and it seems to idle fine. The low idle causes a low frequency vibration throughout the entire car. It is extremely annoying. Any ideas?

My 2000 RX develops a similar pattern to the one you describe after driving it only around town at low speeds with little if any sustained highway driving. If I take the vehicle on the highway and drive an hour or two at highway speeds (65-70 mph), the rough idle is gone after returning to town. Repeat as necessary.

HEY SRX! I have had the same exact problem as you this last couple weeks. Mine also goes away when I hit 65-70.. Did you ever end up figuring out what the cause was or were ever able to make that go away??

[trankie]

I had a very similar problem. The vibration (and sound) would disappear either at Neutral or when I turned on the lights. The dealer replaced a gasket of some sort, and voila, the problem went away. The car is so much quieter now.