Jbthompson

Hi everyone. I searched this and wanted to get some recent input from you all. I cleaned the throttle body MAF sensor about a week ago thanks to the tutorials on this forum. I was noticing yesterday that when I come to a stop light without the AC or anything on, my car is idling in drive around 600 rpms, maybe a little lower. In park its 800ish rpms. If I have the seat cooler on or have the climate control running, it idles at 800ish rpms. It doesn't feel as smooth as I think it should at 600 or less rpms. Is this a normal range? I almost always have seat coolers or climate on so I have never noticed this lower idle until now.

Johnhav430

I think it's normal and that there aren't any adjustments to the idle speed....it's been a while but I believe if AC is on the idle increases? Would be simple to test, just never gave it any thought. Just that I have thought before the idle is rather low...

Jbthompson

Yes if the AC or any accessories are on the idle increases to 800 which seems more normal to me.

bloomwcjkl

Did you buy a Denso MAF or a cheaper knock-off? I tried a $20 one that was sold as a Denso but wasn't. My idle speed was high. Quickly bought the real Denso for $70 and that fixed that.

Wizard650

I have this same issue.

Jbthompson

I didn't replace anything, just cleaned the throttle body and MAF sensor.

Spdjnke

AJT123

Mine does the same thing, always has. Idles too low with the a/c compressor off. I wouldn't worry about it.

But yeah, I know exactly what you mean. I can feel otherwise non-existent minor vibrations in the steering wheel when it idles that low.

Johnhav430

I paid attention this AM....fully warmed up, in neutral, my car was at 800 rpm. In drive, it dropped to covering the 3rd line from 0. Interestingly, I noticed the first 3 lines are not in increments of 200 rpm as the rest seem. There were also times when that third line became visible, i.e. looks like the rpms were below 600. I think it's normal. I'd like to think any higher is unnecessary wear on the tranny. Too bad the car isn't a stick...

Jbthompson

Thanks for all the insight. Yeah I am idling below 600 with nothing running (AC etc). I guess its normal, odd that its not as smooth as a "normal" idle for this car.

Johnhav430

I almost wonder as well, is the rpm drop a physical thing, i.e. because it was put in drive and slipping, or, does the computer see the gear selector is in D, the car does not have AC on, and it decides to lower the rpms, as if there is a decision tree.....these cars are not as simple as the pre computer cars....

YODAONE

Replaced right and left bank OCV's (oil control valves).on 1999 LS400 wth over 160,000 miles which improved idle.

To be able to report improved idle resulted from new OCV's instead of ECU reset, as a control, I did not disconnect negative battery clamp.

Dman68

Same issue here with my 05 LS 430. 600 rpm with car stopped with tranny in drive and no AC on and noticeable vibration in the steering wheel and glove box buzzes a little. AC on and idle is 800 rpm and everything is super smooth. I with it just idled at 800 rpm all the time when stopped and tranny in drive. Sucks that this is "normal" operation for such a smooth car.

Jbthompson

Interesting. I'm relieved nothing is wrong but it does seem odd that this is normal. Like I said, I almost always have the seat coolers on so that accessory keeps the idle at 800 and its smooth. I wonder too if I had new motor mounts the vibrations would be less. Thanks all for your input!

Hklexus

My 01 idles sometimes at 600 sometimes at 400, conditions being the same(no ac, gear selector in D).