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Discussion Starter · #1 ·
Hey everyone! I just bought a 2005 RAV4 with 69k miles on it - a rarity in southern california. However, I have since noticed that at times it will idle roughly at random points. Sometimes when I pull up to a traffic light to stop, I will see it go to a rough idle. At times it will stay there, at other times the motor seems to compensate and kick up the RPMs to about 800. Where would you guys start? The motor has been well maintained and is super clean.
 

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Discussion Starter · #2 ·
Okay, so I decided it might be a good idea to disconnect the battery so that maybe the computer might 'relearn' some better behavior. Wrong! After disconnecting the battery, the vehicle won't even idle. Any ideas from here from anyone?
 

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I've seen this with my RAV4 also.

From what I've found online, it is either-
1) a weak battery
2) dirty throttle body
 

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Discussion Starter · #4 ·
Clean throttle body

Thanks for the input, I am going to try to clean the throttle body tonight and then perform the following procedure... which I found on another post:

Throttle Reset Proceedure:
It is always important to use a Memory saver when doing a battery disconnect on newer vehicles. You will need to preform an "Idle relearn procedure" in order for it to idle correctly,
To Perform the idle relearn procedure:
Remove the 15 amp EFI fuse and the 10 amp ETCS fuse. Remove the boot from the throttle body and clean the throttle plates. Make sure the throttle plates closed completely. Reinstall the fuses. Turn the ignition switch to the on position making sure the throttle plates are closed when the key is turned on. Install the intake air boot and THEN start the vehicle. Allow the vehicle to idle until the cooling fans come on.

NOTE: It is very common for the computer to lose the idle memory when the battery is disconnected. If there is excess carbon buildup in the throttle body, this causes the low/rough idle speed.

I will let you guys know how it goes.
 

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2008 RAV4 Limited V6
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I've seen this with my RAV4 also.

From what I've found online, it is either-
1) a weak battery
YES! Get the battery load tested. I've heard many people dismiss this because their battery is "brand new"--The first 2 "brand new" batteries in my RAV4 failed at 23 months and 25 months respectively. They're not makin' 'em like they used to.
 

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Discussion Starter · #6 ·
So James, do I understand this correctly?

I am assuming a weak battery puts a greater load on the alternator which consequently causes the engine to have to work harder... thus causing a rough idle?

I guess a corollary question would be, what is an appropriate RPM for an idling RAV4 with a four cylinder? I have noticed on mine that at 700 RPM it is smooth, but when it dips to 600 or below, things start getting a little rough and shaky. Does anyone know what the official RPM should be at idle? I have a Toyota service manual on the way, but haven't received it yet, so I would think there would be some good specs in there.
 

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So James, do I understand this correctly?

I am assuming a weak battery puts a greater load on the alternator which consequently causes the engine to have to work harder... thus causing a rough idle?
It can, especially if it has a shorted cell. Recently my daughter's Altima was taking longer to start and idling rough when the A/C was on. Had the battery load tested and it was only putting out about 10.5 volts with a shorted cell. It failed at 35 months just in time to get a free replacement.

I guess a corollary question would be, what is an appropriate RPM for an idling RAV4 with a four cylinder? I have noticed on mine that at 700 RPM it is smooth, but when it dips to 600 or below, things start getting a little rough and shaky. Does anyone know what the official RPM should be at idle? I have a Toyota service manual on the way, but haven't received it yet, so I would think there would be some good specs in there.
In general, your idle speed should be 750 RPM or so.
 

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Discussion Starter · #8 ·
That's very helpful to know... definitely something funny going on, but no engine codes. I will let you guys know how it performs after doing a throttle body cleaning and reset... if no go, then I will take a harder look at the battery.
 

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Do you do much highway driving? If you only do a lot of short trips, your battery might not be as charged as it could be.
 

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My rough idle was solved by changing the sparkplugs on my 2003. Thought there was going to more to it but changing them fixed the problem and it was an easy job.
 

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I had rough idle on my '04. Finally got to the point of stalling at stop lights. Had the local shop check it and they cleaned the throttle body. I plan on getting the battery checked as Toyota told me a year or so ago the battery was getting old.
 

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Discussion Starter · #13 ·
Cleaning the throttle body / throttle reset procedure did the trick

Well, I believe that the problem looks to be solved at this point. Here are the steps:

  1. Removed the air cleaner assembly and rubber hose feeding the throttle body. (Discovered a fair amount of carbon around the lip of the valve.. I am suspicious that the valve was getting stuck in certain positions because of the carbon)
  2. Placed a couple of bricks on the accelerator pedal to hold it down in a 'full throttle position'
  3. Turned the ignition key on (not starting the motor). This actually opens the valve completely and keeps it open for cleaning purposes.
  4. I used some brake cleaning aerosol spray in conjunction with a tooth brush to clear out the body. I also gently scrubbed and cleaned the butterfly valve itself (note of caution here to be gentle so as not to bugger up the motor for it). Carburetor cleaner would probably have been better, but I didn't have any in my garage at the time.
  5. Turned off ignition and removed bricks.
  6. Reassembled a few vacuum hoses as well as the air cleaner assembly.
  7. Pulled 3 EFI fuses and 1 ETCS fuse from the fuse box under the hood.
  8. Replaced the fuses and started the vehicle.
  9. Let the vehicle run for about 30 minutes until the cooling fans came on.
  10. Took the vehicle for a test drive and, at least at this point, no rough idle any longer.
This post was very helpful as an original reference to the throttle reset procedure - it worked great on mine which is a 2005:


http://www.rav4world.com/forums/99-4-3-mechanical/146322-rough-idle-4cyl.html


Thanks to everyone for posting, what a blessing!:smile
 

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After reading this I was inspired to clean my throttle body. For years my idle has been very rough, it shakes the whole car although it never stalled. It would idle around 500 rpms.

After taking off throttle body I discovered the idle air control valve was stuck. After cleaning with throttle body cleaner and reinstalling the car idles great at around 800-900 rpm.

Thanks all for the inspiration, this has been bugging me for awhile. Hopefully my gas mileage will improve as well.
 

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Discussion Starter · #15 ·
Congratulations! I was hoping someone else would benefit from what I was dealing with.
 

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I will say thanks in advance because I will do this just because I haven't yet and have high mileage. This forum really rocks for getting good information for our Ravs.
 
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