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Rough idle came back

3K views 13 replies 8 participants last post by  Oxmix 
#1 ·
Hi all,

My 2006 Camry LE 4 cyl has a rough idle again.
You can feel it when braking (as you get down to under 15 mph)
and at idle speed of course. It is worse when in gear and worse
yet with air conditioning on.
This first started after a water pump change and the computer reset that follows that. I had the throttle body cleaned at a shop and rough idle went away after 2-3 weeks,
idle was then purring again. Gas mileage was restored and then some immediately after that cleaning.
Now about 2 1/2 months later it is rough again and gas mileage around town has tanked. I thought at first maybe overly hot weather in middle to high 90s was taxing the car with air cond. on but last night was low 70s at best.
Any ideas? Car has 105k on it now. It performs fine, idle is consistant at 700. I plan to drive on the interstate next week so I will know for sure how the gas mileage is doing. Thanks!
 
#2 ·
Idle should be about 700-750 so it isn't off any. If spark plugs were missing it would give you a mil so that isn't it, but it is about time to consider changing plugs anyway. The VVT-i may not be working correctly and that usually involves tearing the top end apart and cleaning it, but some oil tratment designed for cleaning valve lifters might also do some cleaning here and degunk the VVT-i. It's cheap to try.
 
#3 ·
It may have appeared after the water pump, but there is no relationship. Sorry to say, its the nature of the 2AZ-FE beast. A combination of I4 balance, engine displacement and age/miles. Its a very common complaint with most I4's of any manufacturer, any displacement. Your options are a buy v6, or take steps to lessen it. But it will never completely go away and there is nothing wrong with your engine.

I have a whole host of things you can do to lessen the shaking if your interested.
 
#5 ·
It did appear after the pump. I got the pump at 98k and bought the car new so it was obvious to me. It was said the computer gets reset and now reads the T.B. as being dirty so I had that cleaned and the gas mileage went back to normal and then some. The car purred again after a few weeks, I assume the computer finally cycled all the way through at that point and said all is good. You really can't tell it is running while in park/neutral and can barely tell while in gear.
I'll know a little more when I take it on a trip here real soon if it sucks gas too. City driving is more subjective and we have a lot of traffic/lights where I live.
...They did say the T.B. was dirty when it was cleaned and I puffed smoke for the first 10-15 minutes afterward, so I know the cleaning had to be done well. Thanks

It may have appeared after the water pump, but there is no relationship. Sorry to say, its the nature of the 2AZ-FE beast. A combination of I4 balance, engine displacement and age/miles. Its a very common complaint with most I4's of any manufacturer, any displacement. Your options are a buy v6, or take steps to lessen it. But it will never completely go away and there is nothing wrong with your engine.

I have a whole host of things you can do to lessen the shaking if your interested.
 
#6 ·
I'm not saying it didn't appear after the pump. But I am saying its a coincidence unless your having temperature problems, unless the pump replacement included a thermostat swap and they changed the temp. I'm answering another guy with the same problem right now, check out the list I gave him, the same applies for you.
 
#7 ·
Do your RPMs drop and stay low almost dyeing. That's a sign of a bad A/F Sensor. You can get a cheap OBD11 scanner at harbor freight. Make sure it has sensor voltage too. Here's what the AF and O2 sensors should read.
AF Sensor 1 an 2 . 1 on top for 4 cyl.
309377

O2 Sensor
. Keep the engine speed at 2,500 rpm and confirm that the displays of ”A/FS B1 S1” and ”A/FS B2 S1” are as shown in the illustration.
Confirm that the display of ”O2S B1 S2” changes between 0 V to 1 V with the engine speed at 2,500 rpm.
309378

. INSPECT FUEL CUT OFF RPM



  1. Increase the engine speed to at least 3,500 rpm.
  2. Use a sound scope to check for injector operating sounds.
  3. Check that when the throttle lever is released, injector operation sounds stop momentarily (at 2,500 rpm) and then resume (at 1,400 rpm).
309379


If you have a OBD11 you can unplug your AF sensor and see if the numbers are better. The numbers will hold steady in limp mode. AF sensors should read a steady 3.3 volts, or right up to it. Your EQ will look good also. O2 will be better like 0 to 1.
Also you may get a wif of fuel from time to time. That's because the sudden drop in RPMs and low idle affects the VSV and it dumps an excess amount of fumes from the fuel tank.
 
#9 ·
I get this too recently 2003 Camry 2AZ-FE over 150K miles original owner. No codes and all of my real time data is good. Plugs good, engine all original, checked sensors with Multi-Meter.

Replaced fuel filter in tank, fuel pump since I was in the tank, cam position sensor even though it original one tested good.

Maybe I will just try replacing the A/F sensor even though it is not tossing a code. Cleaned MAS for good measure it was very clean though. Never cleaned the TB. The last time I had to clean a TB on a Toyota was my 1995.5 Tacoma which is in my front yard as I write this! I have a TB gasket and intake manifold gasket on hand because I was thinking about taking them off and cleaning them and a crank position sensor since the OEM one is still on it even though it tests good!

I drive my 2003 2AZFE like I just stole it and am playing GTA and it has been fantastic. It still does not burn any oil between oil changes that can be seen on the dipstick and it is the fastest (stock) 2AZFE Camry/TC I have driven and I have driven a lot of them! In fact it will smoke my wifes 2007 2AZFE. I think people that have issues with them either broke them in wrong or they just do not maintain them well. I am a bit extreme with maintenance and my Camry is a manual 5spd and was built in Japan.
 
#10 ·
"it is the fastest (stock) 2AZFE Camry/TC I have driven and I have driven a lot of them! In fact it will smoke my wifes 2007 2AZFE. I think people that have issues with them either broke them in wrong or they just do not maintain them well. I am a bit extreme with maintenance and my Camry is a manual 5spd"

the manual transmission 2AZs are faster than the automatics, so you will "smoke" those every time
 
#11 ·
It also owns any fwd GM car with the 3.4V6, 3.5V6, 3.8V6 until about 70mph then those V6's start to slowly but steadily catch me and by 85 they are starting to very very slowly over take me.

It is nothing I did I just got a really good one off the assembly line! I have done a lot of work with Corvettes and import sports cars and if you drive 20 of any given make and model all new built at the same plant the same year some will just be faster and handle better than average and some will just be dogs. Same thing happens with rifles you will always come across some that tack drivers out of the box and some that cannot hit the broad side of a barn out of the box.

Yes a manual can be an advantage but that said very few modern super cars or sports cars can even be ordered with a manual. The Corvette makes due with a very conventional automatic internally.
 
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