# Rough idle in gear only



## abunai (Aug 2, 2003)

I have a KA24DE. Auto trans. All factory.
Idle's fine out of gear. Good power. 
Cleaned the injectors. Compression all good and even. TB cleaned out. Cleaned out EGRvalve. Plugs, wires, cap, rotor all good. Checked for vaccum leaks and couldn't find any.
Idle out of gear is 900rpm, in gear 800rpm. 
Out of gear runs smooth. Throttle responce is great. 
Once it's dropped in gear idle is rough enough to feel, and hear, it through the steering wheel and dash. 
Any ideas?????


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## rogoman (Dec 16, 2004)

If it's extremely rough, the IACV valve may need cleaning or the fuel injectors may not be flow balanced.


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## abunai (Aug 2, 2003)

*Better*

I cleaned the IACV (AAC valve).
I plugged the hose going to the AIV valve.
Cleaned the EGR valve.
Had to raise the idle to 850 in drive.
Much better. 
If I lower the idle to 750, where it should be, it gets rough. 

Any suggestions?????


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## robert ghee (Jun 16, 2009)

check the timing (http://www.********.com/articles.php?id=161707) i turned mine up just a bit and run better and then i turned the idle screw out to idle down. mine idles about 850 in gear great response


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## robert ghee (Jun 16, 2009)

www.********.com/articles.php?id=161707


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## abunai (Aug 2, 2003)

Link didn't work for me.

After doing all the cleaning and plug the hose to the AIV valve, I repaired a exhaust leak.
Seems to have lost some power.
I think the muffler may be plugged. I have lifetime warrenty on it so I'll change it and see what happens.


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## abunai (Aug 2, 2003)

I had the injectors cleaned and balanced about four months ago.
Idle was still rough in gear. 
One died about a week later and I replaced it with a Redline rebuilt one. 

Anyone know if the O2 sensor has anything to do with the idle????
The lights on the computer flash at idle, so I'm thinking it's working.


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## rogoman (Dec 16, 2004)

The O2 sensor is not monitored by the ECU at idle. What specific lights are you referring to? During normal operation there should be no flashing lights of any sort. If the check engine light is coming on, then the ECU is setting a fault code; do an ECU code readout to determine the code.


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## abunai (Aug 2, 2003)

The two lights are the ones on the ECU. According to the maunal they are suppose to flash one to the other showing the ECU is monitoring the O2. 
Same two lighte that are used to pull codes.
I have no codes when I check. 

I'm thinking I may have a small Vaccum leak that I can't find.
Reason for asking if the O2 is used at idle is because if I did have a leak, and the O2 is used at idle, It would show a lean condition. The ECU shows normal.

Plugs, wires, cap, rotor, air filter, compression all good. 
Plugs show good color. Fuel pump pressure good. 
I'm stumped.
I wish it had a carburator insted of EFI.


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## rogoman (Dec 16, 2004)

abunai said:


> The two lights are the ones on the ECU. According to the maunal they are suppose to flash one to the other showing the ECU is monitoring the O2.
> Same two lighte that are used to pull codes.
> I have no codes when I check.
> 
> ...


If the ECU has two lights on it, then you must have an 89 or 90 with KA24E (SOHC), not a KA24DE. 

Check the vacuum with a vacuum gauge. With the motor fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg.


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## abunai (Aug 2, 2003)

Vac reading is at 19-20 at idle. 
When put in gear it fluctuates between 15 and 18. 
If I open the throttle, it holds steddy at 21.
I must have a vac leak some place. 
Just can't find it. 
Did the carb cleaner spray test. 
Checked the rubber hoses.
Nothing.


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## rogoman (Dec 16, 2004)

If the vac reading fluctuates between 15 and 18 rather then holding steady, there could be an ignition miss or sticking valve. Also a low vac reading could be due to retarded ignition timing.


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## cngarch (Sep 5, 2018)

abunai said:


> I have a KA24DE. Auto trans. All factory.
> Idle's fine out of gear. Good power.
> Cleaned the injectors. Compression all good and even. TB cleaned out. Cleaned out EGRvalve. Plugs, wires, cap, rotor all good. Checked for vaccum leaks and couldn't find any.
> Idle out of gear is 900rpm, in gear 800rpm.
> ...


I HAVE A 1996 infinity I 30 with 270000 miles on it. I did EVERYTHING, nothing worked. Thought it was the timing chain, Bought an engine from Japan. Still Does It. It seems like it is getting the wrong signal from the ECM with the low engine speed while in gear. There is a rotation sensor on the transmission that may not be working properly that gives a bad signal to the ECM. That is my latest theory.


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## rogoman (Dec 16, 2004)

cngarch said:


> I HAVE A 1996 infinity I 30 with 270000 miles on it. I did EVERYTHING, nothing worked. Thought it was the timing chain, Bought an engine from Japan. Still Does It. It seems like it is getting the wrong signal from the ECM with the low engine speed while in gear. There is a rotation sensor on the transmission that may not be working properly that gives a bad signal to the ECM. That is my latest theory.


How are the cylinder compression readings. There may be one or more weak cylinders. Another possibility is one or more dirty fuel injectors.


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## cngarch (Sep 5, 2018)

rogoman said:


> How are the cylinder compression readings. There may be one or more weak cylinders. Another possibility is one or more dirty fuel injectors.


All 180 plus I have Video of test.


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## mascudkoray9 (11 mo ago)

abunai said:


> I have a KA24DE. Auto trans. All factory.
> Idle's fine out of gear. Good power.
> Cleaned the injectors. Compression all good and even. TB cleaned out. Cleaned out EGRvalve. Plugs, wires, cap, rotor all good. Checked for vaccum leaks and couldn't find any.
> Idle out of gear is 900rpm, in gear 800rpm.
> ...


there could be an ignition miss or sticking valve.
Speed Test


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## cngarch (Sep 5, 2018)

If the mileage is high (over 180000) it more likely is the torques converter or the valve in the transmission.


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## murrayjestin7 (11 mo ago)

abunai said:


> I have a KA24DE. Auto trans. All factory.
> Idle's fine out of gear. Good power.
> Cleaned the injectors. Compression all good and even. TB cleaned out. Cleaned out EGRvalve. Plugs, wires, cap, rotor all good. Checked for vaccum leaks and couldn't find any.
> Idle out of gear is 900rpm, in gear 800rpm.
> ...


During normal operation there should be no flashing lights of any sort.
Speed Test


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