RPM drops and raises at idle - Toyota Nation Forum : Toyota Car and Truck Forums

Crlnd132 · 07-13-2009, 12:01 PM

On idle, the rpms drops to 600 and raises again to 800 every 3 seconds and that makes the car shake a lot.
It happens on P, N, D and yo can notice it more on R.
No CEL or anything. What could it be?

PortugalFocus · 07-13-2009, 01:05 PM

how long has it been doing this? If not long, it will shortly.... check the codes.

Axxis8203 · 07-13-2009, 01:12 PM

check and clean your Idle Air Control (IAC) valve and the throttle body. the IAC valve is probably stuck open.

felpz123 · 07-13-2009, 05:11 PM

same with mine, idles rough as hell, and it gets a million times worse with ac on

***96paseo*** · 07-13-2009, 05:30 PM

Cleaning your throttle body is a good place to start. Is it worse when the engine is hot or cold?

Mike Gerber · 07-13-2009, 05:51 PM

I have to agree. Clean your throttle body and your idle air cortrol valve. The problem is probably a sticking idle air control valve. Here's a thread on how to do it:

How to: Cleaning Throttle Body -4 Cylinder Engines- With Pictures

Mike

jtex2717 · 07-13-2009, 07:35 PM

Also just do a whole Sea Foam tune up. You can get sea foam from most parts stores and it cleans out all your fuel injectors, oil, throttle body, and then the deep creep by sea foam cleans your idler jets......trust you will see a huge difference......I do this with every oil change....

Crlnd132 · 07-14-2009, 10:36 AM

Throttle body is clean. Last week the mechanic performed a complete engine overhaul and cleaned injectors, throttle body, etc.
I'll check the IAC

Jimnist · 07-14-2009, 09:30 PM

Check the high tension leads for cracks/burn marks/oil. This can cause a rough idle, that was the case for my Gen 2; shook terribly sometimes at idle. After i re-sealed the spark plug tubes and re-did the top seals, it idles really smoothly most of the time now.

cykaaro · 07-19-2009, 01:44 PM

As well, after cleaning, look at adjusting the idle. Just did mine the other day and made a world of difference.

Crlnd132 · 07-20-2009, 01:35 PM

is there any thread on how to adjust idle?

***96paseo*** · 07-20-2009, 08:12 PM

Having your ignition timing set properly, the idle should be close to 800 RPM with the engine at normal operating temperature.

Rnb187 · 07-21-2009, 03:49 AM

Hi I have a 99 camry 175k miles which has been idling low/rough (625rpm in drive). The cold fast idle has also been lower than usual. In extremely cold weather, the car starts almost as if its flooded and the idle doesn't kick up faster than 1000rpm...summer time is a little better, at startup it jumps to about 1600rpm, but doesn't stay, it immediately drops back to 1000rpm and gradually decreases to 600's as the engine warms up.
I've noticed this happening since I had a failed injector and radiator replaced. The car runs excellent, but at stop lights the car idles a little low/rough and it bothers me because I know its not the way it used to be.

Also, I don't know if this is related but when engine is cold, I notice a ticking sound coming from the exhaust manifold on startup...I changed the exhaust manifold gaskets, but no help.

So far I have replaced the following:

Idle Air Control Valve
4 brand new OEM Injectors
Intake Air Temp Sensor
Engine Coolant Temp Sensor
Cleaned throttle body
Tested EGR valve, it holds vaccuum
NGK Spark Plugs
OEM Ignition wires
ECU was replaced

I would really appreciate anyone's help with this as it is very frustrating spending all this money on parts that don't seem the be the problem. Thank you.

andrewmartin130 · 12-06-2009, 01:27 PM

Quote:

Originally Posted by 96paseo

Having your ignition timing set properly, the idle should be close to 800 RPM with the engine at normal operating temperature.

I am having the same problem, please some advise.
Thanks

andrewmartin130 · 12-06-2009, 01:28 PM

Quote:

Originally Posted by Rnb187

Hi I have a 99 camry 175k miles which has been idling low/rough (625rpm in drive). The cold fast idle has also been lower than usual. In extremely cold weather, the car starts almost as if its flooded and the idle doesn't kick up faster than 1000rpm...summer time is a little better, at startup it jumps to about 1600rpm, but doesn't stay, it immediately drops back to 1000rpm and gradually decreases to 600's as the engine warms up.
I've noticed this happening since I had a failed injector and radiator replaced. The car runs excellent, but at stop lights the car idles a little low/rough and it bothers me because I know its not the way it used to be.

Also, I don't know if this is related but when engine is cold, I notice a ticking sound coming from the exhaust manifold on startup...I changed the exhaust manifold gaskets, but no help.

So far I have replaced the following:

Idle Air Control Valve
4 brand new OEM Injectors
Intake Air Temp Sensor
Engine Coolant Temp Sensor
Cleaned throttle body
Tested EGR valve, it holds vaccuum
NGK Spark Plugs
OEM Ignition wires
ECU was replaced

I would really appreciate anyone's help with this as it is very frustrating spending all this money on parts that don't seem the be the problem. Thank you.

I am having the same problem, please tell me how you fixed this.

Thanks