# Rough idle.



## Altima Idiot (Dec 18, 2006)

97 altima.. It runs fine when driving. When I come to red light after sitting there 5 seconds,it starts to idle rough. At stand still in park it idles rough and erratically. goes from 600-850 rpm's and almost stalls. Anybody know what it could be??
I lost my tail pipe days ago, and now only have on there cat.conv. Would this cause it to idle rough??

Please help.


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## matzinm2 (Jan 28, 2007)

I don't know, couldn't tell you. Mine does that too. I think it could be the O2 sensor.


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## Altima Idiot (Dec 18, 2006)

u don't think it is the MAF !?? My check engine light is on, but tthat has been on for a long time. My codes read O2 sensor. I have read other threads that say when it runs this way,it the MAF sensor.
Where is the O2 sensor??

Thanks.Brian


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## MickeyKnox (Jun 17, 2006)

engine mounts
air intake manifold gasket is very comon in altimas. if it leaks then
your car idles roughly. I am gonna be changing mine very soon.

there are 2 O2 sensors. one is when you open your hood, stand in the middle of the front of your car,
stand straight. look down ward in front of the engine. and there it is. 
it's screwed in the engine and there is a wire coming out of it. it's between radiator and the engine.

the other one is on the bottom. screwed into the catalitic converter, which is in the middle of underneath of your car.

first thing is first. so do tune up. clean maf sensor, air intake, change air filter, spark plugs, check resistance of your
spark plug wires.
people change front O2 sensor annually. because it is responsible for gas and your milage. so get bosch or NGK.
bosch is kind of expensive never use bosch plugs for your car. only use NGK
from NGK Spark plug, NGK Spark Plug wire, NGK Platinum Spark plug for High Performance and Racing.. get gp platinum. don't get iridium and other expensive shit. there is no difference in performance. they just last longer.

by the way ngk.com has O2 sensors 40$ cheaper than autozone's no brand name universal sensors.

it also may be that your catalytic conver is cluged or your rear O2 sensor is gone. do those things above than come back if you need more
help. because there are lot's of things that could go wrong.


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## Altima Idiot (Dec 18, 2006)

Ok, I have only the catalytic converter and that is it...no straight pipe to the muffler,is it losing compression and power,or is it a clogged cat converter?? 

Any help is great!! 

Thanks
Brian


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## MickeyKnox (Jun 17, 2006)

i doubt its cat.
clean your throttle body. do the tune up. 
most probably throttle body, also check for air hose leaks/cracks.
let me know if u need procedure how to do it
its hard to say if the error code is accurate without tune up.
50% of the time the error codes are wrong

u can take ou cat converter and see if it melted or broken or cluged.
in any of those cases change it.

cat converter error may be brcause ur rear O2 sensor is gone. change O2 sensor first then see if u need cat changed.


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## Altima Idiot (Dec 18, 2006)

thanks for your help.new wires,plugs,air filter,just did this about a month ago. U said something about throttle body?? How would you clean that?? 
I need the procedure for that. I would have to get under the car and check the O2 sensor. I think that might be it. All the sudden it just started running crappy. Fine one day,crappy the next. Its weird.

Thanks,Brian


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## MickeyKnox (Jun 17, 2006)

the last post on this thread
http://www.nissanforums.com/u13-1993-1997-altima/124653-stalling-problems-1993-altima-se.html

and can't stress enough: don't spray too hard on the MAF sensor if you are gonna clean it.
but do throttle body first. then if the problem reoccurs clean MAF sensor.
maf sensor is kind of expensive.

I am 70% sure that cleaning throttle body will fix it.

having a manual is a good thing too. 15$ in autozone 

this manual is much better than autozone
PhatG20 - Downloads
complete!!
you can look there how to clean throttle body.

anyway if your cat converter melted or clugged you will feel reduced torque or power on high speeds not on idle. so I heard.
if you deside to buy O2 sensor get it from ngk.com for 60$.(autozone price = $100) you really don't have to change it. it will not affect performance in any way.
it only monitors your cat converter efficiency. bad efficiency is when your cat converter is poisoned which happens when your head gasket is leaking
and antifreeze gets into exhaust. but don't worry about poisoned cat converter. it's very rare.


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## Altima Idiot (Dec 18, 2006)

Wel I was just looking at the throttle bodya little bit ago and I see that the small hose going from the throttle body to the vapor canister came off. Would this cause it to run rough?? I cant seem to find anything else.
I tried to downlaod that maniual an no such luck. It won't download.

Any help would be great!!
Thanks


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## MickeyKnox (Jun 17, 2006)

there is a hose end that goes nowhere. this hose end is attached to maf sensor. but it is not actually inserted anywhere
this hose comes from transmission. it's not supposed to go anywhere. it's just there
in case transmission fluid levels go too high.

so air leaks do cause the problem you described.

but you definetely need to clean throttle body. so you know where air filter box is right?
black box on the driver side of the engine. there is about 4 inches in diameger hose going 
from air filter box and into air intake manifold. so you need to release the end of this hose from air intake manifold(that's where throttle body is). pull it out and then follow the procedures described in linked threads. you will see a plate that can be opened or closed depending on how hard you push the gas pedal.
don't be scared. you can do it.


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## Altima Idiot (Dec 18, 2006)

Well,it is funny the little things that can make ur car run shitty.
I was out there tonight and wouldn't ya know it, I found a little hose,1/8 inch diameter,replaced it, and the car is back to normal.
It went from the throttle body to the vapor canister.
I am good to go ....for now!! LoL !!!


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## KA24Tech (Feb 2, 2004)

I just saw this and I was going to say the hose is most likely the problem. Are there any clamps on either end? If not you might use a little wire tie to secure them.
Glad you found the problem though.

Troy


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## Altima Idiot (Dec 18, 2006)

So am I!!!! Thought I would have to spend big bucks.
Other threads have said MAF sensor,throttle body cleaning.distributor needs cleaned,etc,etc. I don't have ther time or garage or good weather to do that.
I am happy!!

thanks..
brian


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