Hi all,

Only mods on my engine include a MEVI. I am experiencing a roughish idle when the car is in gear - but its the worst in 'D'. In 'R' its not nearly as bad - in fact almost not even noticeable in 'R', however once i'm moving, the car is very smooth and not rough at all. In Neutral or Park its as if the engine isn't running at all it's that quiet. A/C on/off makes no difference to idle - i've checked this. Idle is at exactly ~700rpm according to my emanage (which isn't programmed - just running stock values).

I have cleaned my TB and IACV and it hasn't made much difference - if any.

Normally I would expect a vacuum leak somewhere but how would you check for this? Everything vacuum wise seems to work fine.. MEVI activation etc all work perfectly.

I am suspecting that the transmission may be in need of a service. I have had the car a year and have neglected the transmission til now.

Would a worn transmission cause problems with a rough idle? I'm thinking this because my fiancee has another A32 Maxima and it's gear changes seem better than mine. They're firmer and the wheels spin on 1-2 gear change, whereas mine don't - lol.

I have a Transgo High Performance Shift kit for my RE4F04A tranny which i'll be putting in at some stage. I'm wondering if everything in this kit will cure its ailments?

Any comments appreciated.

Cheers all

 

Coil Pack. One of them is bad. I took mine to the dealer to find out which one it was, then replaced it myself. Engine went back to running smooth as ever!

 

The trans likely has nothing to do with a rough idle.

When's the last time you did a basic tuneup? Plugs, PCV, etc?

Check out your coils, they could easily be failing (as BeZerK2112 said).

No CEL?

 

Hi All - tested all my coils - they're fine according to instructions I found on this site. All new spark plugs too. PCV is fine.

Though - I just thought i'd add this - none of the coil packs had consistent readings. Each coil pack brought back a different impedence reading, but all were within range.

 

bump???

 

could it be a faulty MAF?

 

I had a rough idle when my EGR valve was stuck open. Felt like a vacuum leak. Except symptoms where still there when the car was in P. So this may not be your issue.

 

i'll check this out. Where is the EGR valve?

I assume its somewhere on the IACV? I actually have a spare one from when I changed my MEVI over. Maybe I should clean it out and swap it over and see if it makes a difference?

 

On my 99 its sort of under the throttle body. 95-98 have a different EGR valve and its easier to identify because they kinda look like a flying saucer (sorry, cant really think of how to describe it right now)
here's a picture : http://cgi.ebay.ca/1998-98-NISSAN-MA...QQcmdZViewItem

Check the functionality of the EGR valve. I think you have to rev the engine and see if the diaphragm moves but I'm not 100% on this so do some research or maybe someone on here can elaborate.

 

thanks whlimi - i'll check it out.

 

whlimi - it appears I don't have one of these. Is this an emissions thing? Because I'm pretty sure the Australian maximas have a lot less emissions stuff than you guys. Also my car is a 98 - is it possible it has one with a different style?

I also found a small crack in the throttle body gasket. Would this cause a bad idle?

 

I have the exact issue and I get a CEL P0400 code. Going to be cleaning out the EGR tubes when I get time since I hear they get clogged with carbon.

 

I haven't got any CEL codes coming up - though I remember way back when I was doing my MEVI swap, having a spare gasket left over. I think it may have belonged to this...???

 

I'm not familiar with Australian emission standards and maybe you dont have an EGR valve

The crack in the tb gasket might be causing it if its big enough but if its on there tight enough and you say its small, I dont think that could be the problem.
When I had a vacuum leak it was a tiny cut in my pcv valve hose and it made a distinct hissing sound. See if you can detect a similar sound where air is rushing in from some where its not supposed to be. Recheck all your vacuum lines and find out what that extra gasket is for.

 

Jordan follow the pipe you have circled down -to below the bracket pictured with the 2 screws, below that you'll have the Egr valve. BTW any leak after the Maf will likely cause an idle issue. good luck

 

thanks guys - i'll check all this out. I think i'm missing the gasket for the EGR so i guess this will be a good place to start.

It's such an intermittent thing though. I find idle is worse when its hot rather than cooler in the mornings. I live in a tropical climate, so it gets stinking hot most days.

 

heh well the first thing I went to check out was my throttle body and I think I've found the culprite.

Have a look at this...



You can see the piston (which obviously controls fast idle via the water temperature) has become stuck and the arm which obviously controls the throttle position is bent. At closed throttle there is a 0.5mm approx. gap where air gets through. Crazy stuff.

I replaced the throttle body and now it seems to be running fine.

 

Mine did not look like that, but the piston was not moving. I just put a metal cup between it and the set screw to take it out of the throttle picture. I have not had any trouble with cold starts or idle. You could just remove the spring and lever as well. The Thermal element is $ 118 to replace. Not worth it IMHO.

 

Yeah, well I had a spare TB from when I bought my MEVI from New Zealand. (Came off a JDM Cefiro). Just lucky I managed to have a spare one lying around.

It still has a very slight rough idle, so i'll be tackling vacuum lines and EGR today to see if it improves any more.

Funny things I've noticed after changing the TB are smoother gear changes and when you activate the cruise control, it doesnt surge.. it just goes on.. i had to double check if it had actually come on.

 

Isn't it nice when your car actually works?

 

yes, yes it is...

my fiancee's maxima has just finished blowing alternators... its been over a month and $1500 spent and its finally working again. We gotta face it.. A32's are getting old.. they're gonna have problems.

 

Dont say that! Your going to curse us all! I was surprised that it wasn't one of your coil pacs. I had the exact same problem you described and it was a coil pac. Makes me want to take apart and clean my engine this summer.

 

Try putting some BG-44k in your car too. It wouldn't hurt, but your fuel system may be dirty. That can cause rough idle. When I put that stuff in my car after running through a few tank the idling is back to normal.

 

well i just wanted to say sorry for thread jackin..but i cant post a thread on here yet..but yea i just got a 1996 Maxima with 103k, (used to be a 240 driver)..but yea its idling rough but its weird and kinda have some idea but not sure..okay the car idles funny when it reaches operating temp..it bounces from 800-900rpms to 600rpms..so its funky..but remember its only doing it when it reaches operating temp..i changed 5 out of 6 spark plugs..the last one was kinda hard to get to..anyways i kinda thought maybe that last plug is funky or an injector, but shouldnt it idle rough all the time? thinking maybe an emission component coz i know a some emission stuff only kick in after it reaches op temp..but i dont know what..

on another note i thought all maximas uses n60 maf, but mine has an e60 maf is this right? so sorry for making this long..

the car is running well tho..i just took it on a 6hr drive..lol..

 

Search for throttle body issues and idle issues, and IAC. Might need to clean the TB and the IAC. Check to see if the high idle thermal element is working. Start with these:
http://forums.maxima.org/showthread....light=throttle
http://forums.maxima.org/showthread....&highlight=iac
http://forums.maxima.org/showthread....ght=sparky1562

 

BG-44K??? Never heard of it.. I think i'll need to ---> google

 

Never heard of it too is it something like seafoam?

 

anyone have any pics of how to clean the throttle body and iac valve. Thanks

 

its "industrial strength" fuel injector cleaner. like what you can buy at autozone, but you cant buy this stuff.

your local dealership most likely will have it tho (10 bux under the table...)

 

IT MAY BE ONE OF YOUR FUEL INJECTORS