2001 Rav4 - Rough/Low RPM Idle Problem

Hey everyone,

I have a 2001 RAV4with an automatic transmission and 2L gas engine (Canadian market). I have been having what I considered a rough idle for a few years (rougher then it was new, started a year after purchase, dealer saw no problem), but it has gotten markedly worse as of late.

Once the RAV has warmed up (after ~2mins of driving), whenever I come to a stop at some lights, etc and idle it gets very rough, with a lot of shaking being felt through the wheel, seats, etc. I plugged in my OBDII monitor and here is what I found (click the picture to enlarge):



The car idles around 800RPM for the first few minutes, as it should when the outside air tempurature is warm enough for it not to have to enter thecold start loop and idle @ 1,500RPM. That is to say, the RAV idles at the correct "normal" idle of ~800RPM for the first few minutes of operation.

However, once the RAV warms up, the idle falls to ~500RPM and the truck is very rough. Has anyone else experienced this, or know how to correct it? It is my understanding that the idle on the 2.0L is controlled electronically via the IAC valve, so I cannot manually increase the idle, which I would not want to do because it would idle far to high when cold.

I am stumped - ideas?

Thanks!

[Autobeat]

Originally Posted by amorak

whenever I come to a stop at some lights, etc and idle it gets very rough,

Has anyone else experienced this, or know how to correct it?

I think we have a similar Rav. I experience the same thing when stopping. The idle goes down to below 800rpm, and generally shakes the Rav. It usually goes back to 800rpm after a few seconds. Interested as well if there is a known solution for this.

I am glad to hear others are experiencing the same problem.... Maybe we can pool our thoughts and come up with a solution

[ian g]

My 4.1 idles at 650-750 and purrs like a baby (unless the fans come on if the engine is getting hot in a traffic jam, then it does feel a little weird....which could be the answer to one of the problems posted above).

Technically, I suppose it could be the PCV valve or spark plugs or spark plug wires.

I think it may be a weird characteristic among others of the RAV4. Ours is a 2002 with a 2L, 5 speed manual, 70K miles. I notice it when pulling up to a stop and it will happen when I push the clutch in. The engine will momentarly drop real low 500-600rpm then will increase to normal idle speed. It does not happen all the time though. I also notice a drop in RPM when the fans kick on due to the increased electrical load on the alternator.

I have also noticed that the engine rpm will sometimes fluctuate up and down as much as 750-1000 rpm, then it will smooth out. This happens when the engine is cold and backing out of the driveway and pushing the clutch in to stop and move foward. It only seems to happen on colder mornings below 40-45 degrees F. (Hey, I live in Houston, Texas and that is cold for here. I can only imagine how cold it gets in Canada. )

My 2001 also has rough/low idle.
I've replaced both oxygen sensors after the cataytic coverter. Both needed to be replaced but neither had anything to do with the actual rough/low idle problem... but at least I got rid of the Check Engine light.
I also replaced the idle air control valve. Still no help.
Since I've never replaced the fuel filter, I really think this should be my next step. However, I have no idea where this filter is. It's definitely NOT in the engine compartment as far as I can see. Can anyone tell me where the heck I can find the fuel filter on my 2001?
Thanks!
Tha Rav that won't Rev

[philrav4]

same problem here, 02 rav4 awd auto.
I don't have a permanet fix but it helps.(use more gas)
leave the fan on and in the defrost mode, the first or second
setting from the right. the a/c will be on from this 2 positions
or just turn on the a/c in the other vent setting positions.
with the a/c on and running, the computer will set the idle
slightly higher and your engine won't be shaking like crazy
when you stop at a light. try it next time and let us know
how it goes.

Originally Posted by philrav4

same problem here, 02 RAV4 awd auto.
I don't have a permanet fix but it helps.(use more gas)
leave the fan on and in the defrost mode, the first or second
setting from the right. the a/c will be on from this 2 positions
or just turn on the a/c in the other vent setting positions.
with the a/c on and running, the computer will set the idle
slightly higher and your engine won't be shaking like crazy
when you stop at a light. try it next time and let us know
how it goes.

hmmm... that might indicate it's an electrical problem then

running accessories would require more voltage from the alternator, which in turn would require more revs from the engine

maybe upgrading the ground cricuit would help

[Alsone]

I had this problem on a MK1 RAV (1995).

Poor running and coughing at low rpm, hesitation on hard acceleration - nothing for a couple of secs then a big rush.

It turned out for me to be the oxygen sensor in the Catalytic convertor.

I'd had a new catalyst but not sensor and I think they damaged it getting it out.

I went to 2 different main dealers for a period of over 6 months and even had the car driven with protable diagnostic equipment all of which failed to record any fault codes.

In the end a backstreet garage I took it too correctly tested the O2 sensor and diagnosed the problem. New saensor and all was perfect again.

Alfred, it sounds like yours has a different cause if you've replaced the O2 sensor. Check the wiring to and from the sensor.

Also, get a HAYNES manual, best investment you'll ever make. Not as detailed as an offcial manual but gives you what you need as a DIY'er and it shows you where everything is:

http://www.haynes.com/

Just select your region.

Al.

[Phourwheel]

Hmmm...

Just noticed that this summer. Don't feel any difference in how the engine runs (no stalling or anything), but I did notice the RPM go down.

So does anyone know what the minimum rpm is supposed to be?

Cheers!

Philo