this started a few a days ago i was looking for parking then all of sudden the car started to idle really low and shaking. the next day i drove it in the morning it was fine then in the afternoon when i was i was stuck behind this car and it just idle really low out of no where and started shaking and died. i had to put the car in park and start it back up again. it so random it drove fine for awhile again. next time it happen was at a red light it started to idle low again shaking had to put the car in neutral and rev the rpm above 1k to keep it from dying. i decided to bring it to the mechanic but it doesn't happen when i get there. i was so **** i hate when that happens. i told the mechanic and he said its probably a dirty intake and he sprayed some brake cleaner in there it kinda work or not it wasn't happening at that time. it started to idle low again the next day. i might have to leave the car at the mechanic over night to have him test it drive it around to see if it happens to him. any idea. its just so random sometimes it doesn't happen for awhile and just start idling low out of now where. oh one more thing i notice once it start to idle really low i rev it up a few times it kind of stop idling low.

 

Have your IAC valve checked. I replaced mine when it started doing that. It fixed it. And if you wanna save some $$ its easy to install you can probably do it yourself.

 

whats a IAC valve?

 

you had the same problem? i'll check the IAC how much did it cost for you to replace it.

 

It is actually IACV which means Idle Air Control Valve. Controls the amount of air going into the car at idle. It helps the car from not stalling out pretty much. You can either clean it which might be a temporary solution or end up replacing it.

 

Hmm....I seem to have the "opposite" problem, My car idles at 1750 rpms (morning start up) and then it starts to idle at around 1500 rpms afterwards...Then when I put it into "D" it will then start to idle at between 950 and 1150 rpms even when it's warm enough...I wonder what my problem is?

 

Wow those are high rpms. My car idles at 1200rpm in the morning and it IDLES super low im not exactly sure it looks like it was 500 or lower, i think thats bad but theres no stalling it runs perfectly fine. I'll update tomorrow. My 240 had the same problem.. Sometimes it would run perfectly fine then out of no where it'll just stop and die.. Everytime i stopped i gave it some gas.. let my brother drive it and he didnt experience anything its really awkward he thought i was crazy. After he drove it basicly it stopped werid. Yeah try cleaning your IACV you can adjust your idle i believe. GL

 

I've had some random low idle issues as well on my 93 sc300. Sometimes it would get low enough that it feels like it is going to stall, but never does. It has occurred less after replacing my primary o2 sensors. From some searching I have found that it may be a power steering/rack sensor. The OP bypassed the sensor and his car ran fine after. Here is the thread: https://www.clublexus.com/forums/per...idle-read.html

Other than that it runs and idles perfectly most of the time. For reference, my idle is between 1500-2000rpm during first start of the day.

 

i dropped it off to the mechanic and he said it was the injectors are busted. and flooded the pistons. he did a compression test and said 3 need to be replaced. he quoted me about 700 is that a good price to fix it?

 

a compression test tells you ABSOLUTELY nothing in regard to the health of your fuel injectors my friend. Make sure your AFM rubber hoses leading to the intake are tight and not split or leaking air. Next, do a search on your fuel pump ECU. Used fuel pump ECU's run approx $40 and are very easy to replace. Common problem on older and or higher milege SC's. Good luck.

 

mechanic just called and said my engine is dead cylinder #6 is leaking gas or something. how much do u think i can get for the car with a bad engine