[Sach]

I have a '07 Tacoma with the 2.7L engine. It runs great when its cold and idles about 1000 rpm. After it warms up the idle speed drops to about 600rpm. When sitting at a red light the engine begins to idle rough, the seat and steering wheel have a noticeable vibration . If I increase the engine speed by about 100rpm using the gas pedal it will idle very smoothly. The dealer tels me that everything is in spec and there is nothing they can do about it. They say the idle is controlled by the computer and is not adjustable.
Any ideas?

Sach

 

[Jeddak]

Sound like your AC compressor kicks on and puts extra load on the engine. AC will work even if the AC button is off, if you have "windshield" selected on the mode switch.

 

[Sach]

Jeddak , Thanks for the reply, Your right about the AC. I didn't realize the compressor was on in "windshield " mode until I started looking at this problem. Unlike my Crorolla the AC light does not come on when defogging the windows.

You can notice the compressor cycling but that seems unrelated to the problem. The idle is low with it on or off.

If I could just get the idle up about 100 rpm the engine runs smoothly.

Its hard to believe there is not a way to adjust this even a little.

I also didn't realize that there was no mechanical linkage to the throttle until I started exploring under the hood

Sach

 

[bobad]

I have a '07 Tacoma with the 2.7L engine. It runs great when its cold and idles about 1000 rpm. After it warms up the idle speed drops to about 600rpm. When sitting at a red light the engine begins to idle rough, the seat and steering wheel have a noticeable vibration . If I increase the engine speed by about 100rpm using the gas pedal it will idle very smoothly. The dealer tels me that everything is in spec and there is nothing they can do about it. They say the idle is controlled by the computer and is not adjustable.
Any ideas?

Sach

I only have ~300 miles on mine, and it idles very smoothly and reliably at ~600rpm. But...

I think I have some bad effect on my brakes from the low idle you mention. Braking is fine until my truck just about comes a stop. At that time, I have to really mash hard on the pedal to come to a complete stop. I assume the very low idle is responsible for the annoying loss of brake boost. Do you notice that in your truck?

 

[Sach]

Bob, I have not noticed any problem braking. The idle seems to fall off gradually after you stop. It takes about 15 seconds before it is idling rough

Two things I forgot to mention:

If I shift into neutral (automatic transmission) the truck will idle smoothly.

If the AC or defroster is on It seems like the engine actually speeds up when the compressor turns on


Sach

 

[Finnkc]

Funny I get this on my Matrix ... I have been looking for a solution to it .. like you said after I stop at a light my RPM drop to 600rpm and I get a vibration from the engine. Sometimes that idle corrects and shoots up to 1000 rpm or so then drops back down to 700-800 ... its all over really.

its an 5spd 08 Matrix with 400km (not 400,000 btw) on it. I will see if it has to do with the AC pump.

 

[bobad]

If I shift into neutral (automatic transmission) the truck will idle smoothly.

If the AC or defroster is on It seems like the engine actually speeds up when the compressor turns on


Sach

That could be any number of things. In other vehicles, I have noticed that winter fuel blends don't idle as smoothly. It could also be a computer problem, or a small vacuum leak, etc. I hope it isn't too hard to track down. Good luck!

EDIT: It's normal for the engine idle to be higher when the AC compressor is running.

 

[VoodooMaster]

Geeez. I have a 2003 Tacoma, 2.7L engine, and I have the same complaint with the slow idle speed after warm up. My tach reads right at 700 RPM, but I think that it is actually slower. I WANT the idle to be about800 so that the cab vibration goes away at a stop sign. There is an IAC damper connected to the throttle body, right under the linkage connected to the gas petal cable. Anybody have any ideas??

 

[jeffreytcs31]

My land cruiser have the same problem, sometime during stopping the vehicle, the idle drop to 600rpm, and the engine vibrate seem like it is not enough fuel. anyone know what is this? and how to overcome it?