Low Idle In Drive = Vibration?
#16
Lexus Test Driver
i cleaned the air mix path as best as i could, sprayed air intake cleaner right into the two big holes for awhile while the car was idling as per yamae's instructions. had to give a tug on the throttle cable every so often to keep it from stalling, and it actually did stall twice. i also reset the ecu and gave it a decent thrashing and it really didnt seem to make any difference, if not a slight improvement directly after cleaning it. now its pretty much the same as it was before. next i wanna take off the throttle body and thoroughly clean it as best as i can, and not leave that job to someone else this time.
#17
I think you'll find the biggest difference in cleaning the throttle body... I had a low idle problem that would sometimes stall when exiting the freeway and coming to a stop. Would start up fine... but cleaning the throttle body fixed my problem. It was on a 95... didn't clean the air mix path at all... only the throttle body. Good luck.
#19
Lexus Test Driver
iTrader: (1)
I have the issue also and have not run it down yet. I removed the throttle body and cleaned it thoroughly during my TB/cam/crank seal job and it idles right sometimes while in drive but drops to about 400 sometimes. I'm kind of annoyed at myself for not changing the fan bracket while I was in there since I now believe it is bad. I wonder if that could affect the RPMs? I did OEM motor mounts last summer too.
#20
Luckily I get no vibration, just the 400-450 rpm idle. Also, if I reset my ECU it will idle around 200-250 rpm with no vibration, very quiet and you would think it would die but it doesn't. It carries on like that for about an hour and goes back to 400ish with no lights or a/c and 600ish rpm with.....Strange.
#22
Lexus Test Driver
so i looked inside the throttle body and it was pretty clean, I sprayed some throttle body cleaner and cleaned inside with a rag and cleaned the air mix path again and it made no difference of course. it's never about to stall, just kind of low and there'll be a slight vibration when it's warm unless I turn the lights at least 1 click or turn on the A/C
#24
I am having the same issue. i pulled the codes and i got p1400 (sub TP malfunction). This is the one for the traction control and consequently the more expensive of the two. Ill be doing the replacement soon and will have an update
#26
Lexus Test Driver
does anyone suggest a particular method for finding a vacuum leak? my throttle body and air mix path are clean, and before replacing any sensors i want to be able to completely rule out (or discover) a vacuum leak
#27
Moderator
So you still have the problem. The next step you might try is to check the fuel injector professionally using a sound scope.
A skilled mechanic can distinguish a bad injector with it. A needle valve in the injector sometimes sticks and causes the problem and this can be checked by the sound scope if he is experienced. Sometimes only a clogged injector causes the problem. In any case, the waveform of the injector sound and the FFT(Fast Fourier Transform) results can help you to identify the poorly working injector without removing it.
A skilled mechanic can distinguish a bad injector with it. A needle valve in the injector sometimes sticks and causes the problem and this can be checked by the sound scope if he is experienced. Sometimes only a clogged injector causes the problem. In any case, the waveform of the injector sound and the FFT(Fast Fourier Transform) results can help you to identify the poorly working injector without removing it.
#28
Lexus Test Driver
iTrader: (1)
Has anyone had any luck running this issue down? My RPMs were bouncing around while driving and idling. I disconnected the battery for a lil and that speed the bouncy needle. Yamae has a good suggestion about the injectors though. While the needle was bouncing the car was lacking for take off power and felt to me like it was not getting any fuel.