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Rough idle on a 2k1 1MZ-FE

17K views 23 replies 14 participants last post by  xxpanipuri  
#1 ·
Hi everyone,

I have a 2k1 V6 Camry that has trouble maintaining a steady idle. It doesn't stall, but I when I let off the gas and roll to a stop, I can see the tach bouncing up and down. When I stop, the car idles very low (around 400-500rpms) and shakes.

The diagnostic code says the idle control something is malfunctioning.

Any help would be greatly appreciated.

Thanks everyone!
 
#3 ·
^ Most likely.

What happens is that it gets clogged with oil (from crankcase breather).

You can try cleaning it out with carb cleaner / throttle body cleaner. Just make sure the can says that its safe for sensors and stuff.
 
#4 · (Edited)
Thanks everyone!! Problem solved.

It turns out the diagnostic codes don't always tell the entire picture. It was an EGR problem but not directly related to the valve itself. The diagnostic code told me it was an IAC issue.

There was a sticking thingamajiggie [vacuum relay?] underneath the big plastic cover. It hooks up 3 hoses and one runs to the EGR valve. When I unplugged that hose, the hesitation went away shortly, then came back.

I squirted some throttle body cleaner stuff into it. All of the sudden, no more stumbling at idle and hesitation at acceleration.

This place rocks! :)
 
#5 ·
On the prevention side, what oil are you using? If it's a mineral (or even weak synthetic) that has a particularly low flash point, your engine may be generating more oil vapor than normal, thus speeding the gradual accumulation in the recirc system. It certainly seems that it's a little early for this to be happening to an '01 (unless perhaps it suffers some form of particularly severe service). An oil with a significantly higher flash point, compared to what you're now using, might slow or prevent this problem from happening again.
 
#6 ·
I'm using 5w30 Mobil 1.

I really don't think it's an oil vapor issue because the hose connects all the way over from the airbox (not from the crankcase or near the throttle body). There's 2 hoses that connect on the clean air side of the filter. This is the smaller one that runs to the engine and the little [vacuum relay?] at the end of that.
 
#8 ·
my 99 1mz-fe doesn't idle rough when engine is not warmed up,
but after i drove it on highway for a while, i guess the engine should be warmed up, and coming to traffic light, i can feel the car shakes a little sometimes and the RPM has minor flucutation, if i gives a little gas, the rpm won't fluctuate and the car doesn't shake anymore
anyone has any input what the cause is?
 
#10 ·
My car seems to idle a little more roughly then I remembered when I got her...my mechanic says that the engine mounts get old and don't asorb the engine idles. As for your EGR prob. I had it too, only mine stayed closed, stalling my car. To keep it clean-once and a while drive your car like you stole it!- Cleans out crap and keeps things open.
 
#12 ·
mine does something similar i have a 2000 le v6 and it started after i cleaned the throttle body.

when the engine is cold and i start the car up its fine.

but once the engine is warm and i start it back up (ie after going to starbucks to get some coffee) :)

it idles around 400-500 rpm and seems ready to stall....and when i put it into reverse it stalls.....

unless i give it some throttle and then reverse then i'm fine..... otherwise the car runs fine...
 
#16 ·
I cleaned out my throttle body today. Didn't know it would make such a difference. That along with a gas treatment, oil change, and new air filter makes the car feel much better.
 
#21 · (Edited)
xxpanipuri said:
DO YOU HAVE TO remove the IAC to clean it/lubricate it....
No, but you can do a much better job of cleaning it, if you remove it.


or can you do that by just removing the throttle body (going to go home and read in my haynes manual tonight)
You can do that to. Theres a hole inside the throttle body that leads to the IAC.

So you can just spray inside that hole with carb cleaner or brake parts cleaner. It'll drip out thru one of the metal pipes on the bottom of the IAC.


also if i do remove it should i replace the gaskets??
Yes, if you remove the IAC from the throttle body, replace the gasket (its a rubber gasket).

Also replace the throttle body gasket, although some of them are metal and reusable. If its metal, its up to you, but its always a good idea to replace any gasket that you remove.
 
#22 ·
thanks for the info man :) appreciate it :)

i'm going to do some more reading on it tonite in the haynes manual and go and maybe try to remove it tonight and go get the parts....so that i can put it back together....good thing is my wife's outta town so i can use her car while mine sits inside my garage with the tb/iac removed :)



88 LE said:
No, but you can do a much better job of cleaning it, if you remove it.




You can do that to. Theres a hole inside the throttle body that leads to the IAC.

So you can just spray inside that hole with carb cleaner or brake parts cleaner. It'll drip out thru one of the metal pipes on the bottom of the IAC.




Yes, if you remove the IAC from the throttle body, replace the gasket (its a rubber gasket).

Also replace the throttle body gasket, although some of them are metal and reusable. If its metal, its up to you, but its always a good idea to replace any gasket that you remove.