# Rough Idling...



## seaofprajna (Jul 21, 2004)

ALoha everyone,
I've just replace all of my fuel injectors, however the initial problem of the rough idle was not fixed.... I've replaced the computer and have encountered the folowing problems/symptoms... I own a 1996 nissan altima, and when I am at idle in any gear or neutral I find that the rpm's bounce between 500 and 1000 at quite a rapid rate, every so often leading the vehicle to completely stall out... since I replaced the fuel injectors I also hear a high pitched hissing or whining when I push on the gas lightly to moderately hard, after the initial acceleration the sound goes away and the rough idle is no more an issue, only at idle....I've recently replaced the spark plugs, wires, distributor cap and rotor, oil, fuel filter and water pump, but am quite at a loss as to what is causing this... I doubt that it's the computer seeing that no matter what gear I'm in the idle is rough, I've read about a few things and have also been told to check the oxygen sensor, but I'm not sure.. any thoughts or follow up questions for clarification would be much welcome,... thank you very much,
Shaun Prajna Sakya


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## dolla82 (Oct 18, 2004)

i have a 1994 altime GXE with 128000 milles on it. My car started doing the same thing yesterday. It started when i was bored and decided to take the spark plugs off and make them look nice and put them in order, well i wound up putting two of them in the wrong place after. I put them back then the car would idle rough and putter from 1000 to 500 and it would also whine. I talked to my dad was is a mechanical engineer and he told me check the vacuum lines so i did and everything was good. So im finally taking to my dads shop tomorrow and ill find the verdict. And ill let u know what we have to do to fix the problem. I hope this helps.


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## seaofprajna (Jul 21, 2004)

*thanks a ton*

Interesting to hear.... I think that maybe there is a slight vacuum leak on the end of the fuel rail, but I need to check that out for sure... my car only has 80,000 miles on it so Ihope this can be repaired.... waiting for some good news.... aloha, shaun


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## dolla82 (Oct 18, 2004)

Didnt end up going today, the weather was horrible but im deffinetly going on tues mourning. I was told today that the misfiring in the cylinders might have caused a carbon build up in the EGR valve. so that might be a another thing but for now its just a mistery. Let me know if you hear anything from anyone else this is really bugging me. Take care


-Khash-


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## dolla82 (Oct 18, 2004)

*Problem Fixed*

The problem was my injectors were a little clogged so no the car runs great! dont use the injector cleaner from the store, get the can that hooks up directly to the fuel rail. Hope this helps


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## seaofprajna (Jul 21, 2004)

*still checking....*

I hear a whistling sound so I think it could be the vacuum line... not too sure how to check the line for integrity tho.. any thoughts? plus a funny thing I discovered is that the problem seems to subside when I engage the air conditioner, idle seems much more stable and the problem nearly goes away.... still working it through... also the fuel injectors that I JUST repolaced were supposeddly pressure tested and ohm tested.. does that necessarily mean that they aren't clogged? Also, where exactly is the EGR valve so I can take a look at that?... if you have any aditional revalations it would be appreciated.. aloha Shaun


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## gringoloco (Nov 4, 2004)

I've had an idling problem - though not as rough as yours - i posted a thread - my problem seems to be something with the spark plug wires/distributor area (it also runs rough at other times though) and I don't have a whining sound. Anyway - I'm looking for answers for that area - and it may be what's affecting your car - I started to have trouble with it after I had wires/plugs replaced - later I had the distributor replaced which helped my engine starting but the idling/missing was still there...but something seems to be causing the wires to go bad - they've been replaced several times now (2x).
-Ben


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## dolla82 (Oct 18, 2004)

*Problems Back*

 this is to seaofparjna. Everything was running fine for about a week or so then it started back up. I was reading around and saw some people talking about the knock sensor. whick is located under the intake manifold. they say try to relocate it or replace it, but before i even bother with that im going to check the ecu because i hooked a snap-on computer to the obd2 port in the fuse box and it said everything was fine even though it was idleing rough, so i want to see if the stock computer is sending me any codes. And if you want to check for vacuum leaks go buy a can of carb cleaner and start spraying around the intake area and if the idle go's up then u have a leak if not then no. Are you doing anything to check out ur car or have u given up? let me know. take care and goodluck man. ill let u know what my situation is in a couple days


-Khash-


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## Javier Callico (Nov 13, 2004)

*Mine is doing exactly the same !!!*

My car is doing the same. Seems like it happens a lot for this car.

How did you guys finally fix the problem ?


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## Joe_Nizmo (Nov 15, 2004)

I've had that problem too..... change your EGR valve and your PCV valve....
as far as the hissing noise and the wild idling...sounds like you have a vacuum leak , maybe a crack in one of vacuum lines.... ALOHA from Ewa Beach


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## Joe_Nizmo (Nov 15, 2004)

*the common problem for altimas*

one problem is that the top part of the radiators for the altimas are plastic , so if your race it from time to time expect it crack....When my radiator cracked I was about 20 miles from home and as long as I didn't rev my motor over 2 grand it wouldn't spray out any antifreeze... 2 grand equals about 50 somethin mile an hour...that really sucked!

another problem is that the seals in the distributor wears out and oil leaks in the distrbutor and it's shut down time....hehehehad that happen to me and boy was that expensive.....


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## big_aluminum_wing (Nov 12, 2004)

Yep, mine did the same sort of thing - but replacing the EGR valve did the trick. You can find the valve on the topside of the engine in the center near the firewall. It looks kind of like a little spaceship (for lack of any better term) and will have a vacuum hose coming out of one side.


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## Javier Callico (Nov 13, 2004)

*What to do for rough iddling?*

I'm a little confused now. What you recommend me to do first to solve the rough iddling and excesive gas consume? Do I have to replace the EGR Valve or the Intake Manifold Gasket (upper or lower)?


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## big_aluminum_wing (Nov 12, 2004)

First off, you'll want to make sure that your EGR valve and PCV valves are either replaced or working correctly. If your car has higher miles (i.e. over 80k, you'd be best off just replacing them since they'll most likely go bad soon anyway). Either of these could cause a rough idling engine. Beyond that, then maybe the manifold gasket, and in an extreme case or two, it could be the radiator as someone else mentioned. Find yourself a parts store and a buddy with some tools and try replacing those two things. The PCV will only set you back a few bucks, but the EGR is a wee bit more expensive...so bring your wallet.

Speaking of which, I need to replace my PCV valve.....


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## KA24Tech (Feb 2, 2004)

Try to check the Throttle Position Sensor to make sure it adjusted correctly. Also try running a premium fuel system cleaner such as BG 44K through it with a tank of premium fuel. The whining is the fuel pressure regulator at the end of the fuel rail and you might try disconnecting and plugging the vacuum hose attached to it to see if itchanges in pitch or if the idle quality changes.

Troy


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## khatrisa (Aug 23, 2004)

Are the PCV and EGR valves easy to replace or will I have to take it in? 

If I am able to do it, any one with experience got any suggestions to facilitate?

Thanks


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## niv (Dec 10, 2004)

I think the EGR valve is a complex job.. but the PCV valve is pretty simple to do yourself.


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## khatrisa (Aug 23, 2004)

niv said:


> I think the EGR valve is a complex job.. but the PCV valve is pretty simple to do yourself.


Got any suggestions or instructions or know of where I can find instructions.

Thanks for the help!


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## niv (Dec 10, 2004)

Im sure the Haynes manual would help you.


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## 95Alty200K (Dec 15, 2004)

The PCV is definitely *not* an easy replacement on the 2.4L Altima 4cyl.

On my '01 Accord, it's right on top of the valve cover, it couldn't be easier. On my sons '95 Alty, it's buried under the intake manifold on the passenger side, a real PITA. Check for a price at your local dealer, you'll be surprised what they quote you to do this job.


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## droped-low (Dec 7, 2005)

*1994 nissan altima run rough and hard to start wen hot u have to hold the gas wide o*

hi i am working on a 1994 nissan altima GXE run rough and hard to start wen hot u have to hold the gas wide open what shood i look at it has new cap and roter and new wire and plug r not bad and pulled code from computer got code 55 that no code. what shood i i look at next this car ben a pain hope some one can help mean soon look for word to here from u guys and girl talk to u all soon chris


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## jovanni (Mar 29, 2005)

Joe_Nizmo said:


> I've had that problem too..... change your EGR valve and your PCV valve....
> as far as the hissing noise and the wild idling...sounds like you have a vacuum leak , maybe a crack in one of vacuum lines.... ALOHA from Ewa Beach


sup ,im gonna replace my egr and pcv valve due to rough idling,is there anything else i can replace due to r idling,oh yeah i just noticed my bottom rubber seal on the distributor is half hanging out!should i spend the 500 fixing this first?thanx


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## LONDONDERRY (May 19, 2004)

jovanni said:


> sup ,im gonna replace my egr and pcv valve due to rough idling,is there anything else i can replace due to r idling,oh yeah i just noticed my bottom rubber seal on the distributor is half hanging out!should i spend the 500 fixing this first?thanx


Go simple first
Before you spend money on replacing parts, I suggest you clean out the throttle body, EGR valve(make sure you have a new gasket) and Idel air control valve, they might just be dirty. In addition, add some fuel injector cleaner (BG Fuel Injection System Cleaner are reccomended on this forum) and a tank of premium gas. Try all that first and see what happens. 

On the distributor, I think you can just buy a new rubber seal, but keep and eye on it. If there is oil present in the distributor then you have to replace the unit as whole. Like I mentioned just keep an eye on it.

Good Luck
Frank


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## jovanni (Mar 29, 2005)

LONDONDERRY said:


> Go simple first
> Before you spend money on replacing parts, I suggest you clean out the throttle body, EGR valve(make sure you have a new gasket) and Idel air control valve, they might just be dirty. In addition, add some fuel injector cleaner (BG Fuel Injection System Cleaner are reccomended on this forum) and a tank of premium gas. Try all that first and see what happens.
> 
> On the distributor, I think you can just buy a new rubber seal, but keep and eye on it. If there is oil present in the distributor then you have to replace the unit as whole. Like I mentioned just keep an eye on it.
> ...


hi,thanx for the straight forward reply ppreciate it,do i leave the t/b attatched to clean or better to take out and clean?also read somewhere in here that i can take iacvalve itself off with 2 screws on the top,without replacing the gasket ,is that true?do i use carb cleaner to clean egr,iacv,t/b?


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## jovanni (Mar 29, 2005)

jovanni said:


> hi,thanx for the straight forward reply ppreciate it,do i leave the t/b attatched to clean or better to take out and clean?also read somewhere in here that i can take iacvalve itself off with 2 screws on the top,without replacing the gasket ,is that true?do i use carb cleaner to clean egr,iacv,t/b?


thanx,again umma need the luck


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## LONDONDERRY (May 19, 2004)

jovanni said:


> hi,thanx for the straight forward reply ppreciate it,do i leave the t/b attatched to clean or better to take out and clean?also read somewhere in here that i can take iacvalve itself off with 2 screws on the top,without replacing the gasket ,is that true?do i use carb cleaner to clean egr,iacv,t/b?


You can leave the throttle body attatched, just remove the round duct coming from the air filet housing, its a large c-clamp. Then open the throttle plate and take air intake cleaner and spray in it and use an old toothbrush to scrub it they spray again, let it dry and reattatch everything.

Your correct, you can remove the IACV valve, it is two philllips head screws holding it place, you may need to replace the o-ring gasket though. Remove it and clean it in the same mater as the t/b

For the EGV valve, in my opition, if you car has a substancial amount of milage on it, you might as well replace it instead of cleaning it, just make sure its no good first, because it costs about $130 $5 for the gasket.


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## jovanni (Mar 29, 2005)

AGAIN THANX,NOW I HAVE TO PRAY THAT ITLL GET AT LEAST MANAGEABLE WEATHER UP HERE IN BOSTON TO WORK ON THE ALTY LOL


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## LONDONDERRY (May 19, 2004)

jovanni said:


> AGAIN THANX,NOW I HAVE TO PRAY THAT ITLL GET AT LEAST MANAGEABLE WEATHER UP HERE IN BOSTON TO WORK ON THE ALTY LOL


Better do it before Friday's snow storm


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## tallers (Feb 4, 2005)

My 97 Altima had the rough idling problem. Eventually the check engine light came on and the code listed the knock sensor. The problem was the intake manifold gasket was bad. While the car is idling, take a can of carburetor cleaner and spray along the top of the intake manifold gasket. If the rpm goes up at any point, there a leak.

The Stealer wanted $2200 to fix it. It's labor intensive but I did the job myself for ~$100. Six dollars for the gaskets, the remainder for gasket sealer, tools, etc. It took me around 12 hours labor to do the job.

Hope this helps!!!


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## bsmart58 (Dec 9, 2005)

Hi, I had the same problem with my Altima a while back.
We replaced the EGR Valve, it helped about a week.
The dealership then took the intake manifold (I think I have that right, could be exhaust manifold, ) off and soaked and cleaned the ports, there was excessive build up. That fixed it. Hope this helps some. 
(I'm a girl, so I don't know all parts of a car)


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## droped-low (Dec 7, 2005)

droped-low said:


> hi i am working on a 1994 nissan altima GXE run rough and hard to start wen hot u have to hold the gas wide open what shood i look at it has new cap and roter and new wire and plug r not bad and pulled code from computer got code 55 that no code. what shood i i look at next this car ben a pain hope some one can help mean soon look for word to here from u guys and girl talk to u all soon chris




fond out it was the intake intake manifold gasket leak hope this help some one out


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## annesjn (Dec 2, 2004)

tallers said:


> My 97 Altima had the rough idling problem. Eventually the check engine light came on and the code listed the knock sensor. The problem was the intake manifold gasket was bad. While the car is idling, take a can of carburetor cleaner and spray along the top of the intake manifold gasket. If the rpm goes up at any point, there a leak.
> 
> The Stealer wanted $2200 to fix it. It's labor intensive but I did the job myself for ~$100. Six dollars for the gaskets, the remainder for gasket sealer, tools, etc. It took me around 12 hours labor to do the job.
> 
> Hope this helps!!!


I am in the process of doing this myself. Do you have any suggestions for getting the bolts out the hold the manifold to the head? I am down to one last bolt and I can't get to the damn thing easily with a wrench. There is a bar in the way I think from the PCV valve. I have a 96 Altima so it should be simular. Thanks


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## tallers (Feb 4, 2005)

There is a bracket connecting the power steering unit to the manifold. Make sure that is removed. Also, there's a small hose bracket under the manifold at the back of the engine.

I needed myself and my brother to get it loose. It's a bear bu it will come loose eventually. Good luck.



annesjn said:


> I am in the process of doing this myself. Do you have any suggestions for getting the bolts out the hold the manifold to the head? I am down to one last bolt and I can't get to the damn thing easily with a wrench. There is a bar in the way I think from the PCV valve. I have a 96 Altima so it should be simular. Thanks


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