luccig

I keep reading about all kind of low idle issues, hiccups, etc.. but I can't seem to find anything that describes my problem.. so here I go:

Warm engine, 7-800 idle on neutral, when put in drive - immediately the idle goes low, too low, only at the first two lines on the dial (I assume about 400 rpm). This generates some trembling of course, and I am afraid it will go worse and worse, so please give me your best two cents on this.. Thanks for any pointers!

I'm getting to the point I put it in neutral at every stop light.. just to not have the engine trembling ..

(from all the reading I've done I've figured out I will start with IACV clean.. https://www.clublexus.com/forums/per...rol-valve.html

But is there something else I should be doing same time? -- just got this car a few weeks ago, still have another 95 SC400 but there are NO issues with that one, ZERO problems for the last 10 years I've owned it and almost daily driver..)

scENFORCER

Search 'low idle' with the search feature in the Performance & Maintenance section, there's a few threads about this.
I was worried I had the same problem with my '99, turned out to be nothing - and any other '99 I've seen has the exact same (seemingly low) idle. Only difference is that your engine is actually trembling, which was not a symptom with mine or other SC's I've seen.
In one of my threads, a few guys recommended replacing the engine mounts, but with no explanation as to how that would cause/fix a low idle problem. They only said that it worked for GS guys..

On a side note, how did you get a '00 into Canada? As far as I knew they weren't allowed to be imported due to an issue with the immobilizer?

Dougspeed

iTrader: (2)

Mine does the same, but it's more pronounced after running the a/c awhile and shutting it off while it's idling. It dropped so low that it stalled a couple times. Engine doesn't tremble however.

Carfreak70

iTrader: (16)

Same here on my 99' SC400, It has stalled on me once. I cleaned my throttle body and seafoamed it, and it seems to be performing better. Not a major increase in idle or anything just hasn't stalled or acted like it wanted to.

Good luck!

OG Dada

iTrader: (10)

When you say trembling do you mean like bogging down, almost about to shut off? 'Cause my '95 400 idles at the second mark/line as well when in Drive, but it is very stable. And also good for gas mileage. But when in Neutral it idles around 600-800 mark. Again, no issues.

LEXXIUM

iTrader: (1)

I'm having the same issue here on my 00, but the problem is intermittent.
I get a vibration coming to a complete stop and that's when my idle drops, but not every time
And I get a vibration from somewhere between engine and what could be a trany mount.
I'm starting to think its either one of the mounts or trans solenoids possible.

bigwes

I have this same problem as well. But it doesn't happen all the time. When it does, the car has a hard time crushing if u jus let off the brake and don't touch the gas.

luccig

Thanks for the replies guys!

scENFORCER, I didn't have any problems getting the 00 into Canada at all.. just got a clearance letter from Lexus, then all the normal paperwork, bill of sale, title, etc. Then at the Federal approved inspection point, i.e. Canadian Tire, got inspected and form stamped and then registered with the Ministry of Transportation.. nothing about an immobilizer.

Thanks Dougspeed and Carfreak70, it helps to know this is happening to other people exactly like described.. I have read indeed a lot of posts on low idle, they all seem to be similar but not sure if they had a similar solution to this issue.

KingPhilip, trembling I mean like feeling the vibrations inside the car through the chair, like shaking but not as bad yet as to stall the car or anything, just this nagging tremble. Like I said.. I'm just afraid this will go worse if not taken care of..

Thanks LEXXIUM, I got the engine mounts as well, and I'm ready to dive on to changing them, even though my garage at the moment is pretty small and tight, so it won't be an easy job for me.. but I'm thinking even if I'll change them, it won't fix the root of the issue, i.e. low idle when on Drive and foot on the break standstill.

bigwes, yes, same here.

luccig

It turns out the cleaning up the throttle intake with a spray can from Canadian Tire, throttle cleaner I believe it's named, solved my issue. The engine sings nicely, even though the idle rpm is still pretty low on the 2000 SC400, comparing with my 95 SC400.

To my surprise, when I opened up the throttle pipe, which on the 2000 is a PITA since you have to undo some things.., there was a lot of black grime in, it seems the guy that serviced it before put some extra black grease on the lip of the pipe to make it go in easier. I had to clean that up as well, and redone it with just a pinch of grease.

Anyway, I'm a Happy camper now