My engine has been idling strangely recently! It revs up and down, almost to the point of cutting off. Are my spark plugs the problem? What plugs does the 400 take anyway (Denzo or NGK). I'm still a newbie

 

Has anyone else had a similar problem?

 

How many miles are on your car? Plug change is recommened every 60000 miles. I used the NGK Iridium IX plugs. Just cleaned my throttle body and Mass Air Flow sensor tonight. Car idles and runs smoother now.

 

maintrain - where did you get your throttle body cleaned at? i'm plannin' on doing this as well, and also clean my injectors and i'm gettin' the torque master sparks and power flushing all my fluids, and doin' the maf sensor cleaning

 

search for idle problems ..or stall

 

did it myself with stp throttle body cleaner, toothbrush and some shop towels. I followed the instructions from here http://www.lextreme.com/tb.htm but the gs400 is a little different that what's shown on that site for the sc400. Took about an hour. There is a thread discussing MAF sensor cleaning here: https://www.clublexus.com/forums/sho...d.php?t=208854

 

was your A/C on at the time? If not, turn it on.

 

Get an emissions/fuel injection cleaning at your local Jiffy Lube. Cleaning the throttle body is just have of the job. I bet your idle problems will be a thing of the past.

 

Call me **** or particular but I wouldn't let the 'clowns' at a Jiffy Lube even look at my car. Their 'mass production' techniques leave a lot to be desired. I heard of some pretty horrific stories regarding shops like Jiffy Lube. Forgetting to add oil, putting in the wrong type of oil or filter, etc. etc. Of course they are famous for recommending transmission or cooling system flushing when all is just fine.

Just my humble opinion. Take it or leave it.

 

Well get it done at Toyota, Lexus, or a trusty mechanic. That is something that should be done every 15k.

 

I'll have to try cleaning the injectors to see what will happen! I hope this solves the problem, but if it doesn't, should I have the plugs changed next?