As title says, i changed both valve cover gaskets and its idling horribly....when cold it idles ok around 1200-1000 but feels like it misses or stutters....when warmed up its way worse, hunting between 750 and 300 rpms, shakking badly etc...i double checked everything for intake leaks etc...even sprayed some either around UIM gasket to check for leaks....im wondering if its IACV finally crapped on me.

I should add that when driven the car drives beautifully and leaks not a drop of oil anymore...., however when i clutch it to come to a stop it idles almost to 0 before catching itself and even dies sometimes if i dont tap the gas....

plz help, thank you!!

EDIT* new UIM-LIM gasket installed when it was off too...

 

Vacuum leak.

 

Raise idle, spray wd-40 all over the UIM gaskets, if it dies when you spray it, you sir have located your vacuum leak.

 

He did not raise idle, but did spray wd-40 over the UIM gasket(in his post)
Im guessing IACV if it is only the idle that is ****ty, but when you give it gas is ok. All your vacuum hoses connected good? Take your IACV off clean it, and test that all connectors on IACV are functioning. Changed both of my valve cover gaskets, spark pluk gaskets(one was leaking oil) a couple years ago, but did not have issues like you so

 

Thats what i was thinkin.....ill recheck all hoses tonight i did replace a few hoses (breateher hose between both vc, coolant hose on rear of uim n a few brittle vac hoses right under the tb) i also cleaned maf, tb, egr tube and iacv as per the thread on that subject and replaced all gaskets w oem nissan.

 

hope its your IACV and not a harness issue. Moving an old harness around to remove the UIM can break wire on the quickness.

 

My VERY first thought and worry.....but i would think if it was a harness issue it wouldnt only b on idle....it would affect the car w load on and off the engine and at all rpms.....also btw no codes

 

Not if its the IACV because it only takes over at idle, part of the ECU that controls the IACV can fry as well.When I had a screwy idle I first checked for leaks and such and found none. THen I got an IACV code and was relieved becuase I thought I would go to the pull-a-part, swap it out and be done. Didnt fix it. Come to find out the ECU can fry and you need to repair or for most people, replace it. Test the IACV. Should be 30ohms resistance. Then trace the wiring. First check for leaks though, hoses can have a crack

 

Exactly as u stated, unless the wires only affect idle. Maybe a wire that is hitting ground sometime(small split), give it a good visual check. Everywhere. Also when did you clean or replace your air filter, fuel filter, or spark plugs? What I forgot, how is your main ground wire? Or do u have a grounding kit?

 

Replaced fuel filter w z32 about 2000mi ago, spark plugs r ngk platinums replaced same time, and air filter is k&n cone snd was cleaned/oiled last fall......coils are all used off low mileage junk car been on their less than a month....i ohm tested rear injectors since i had uim off....all tested 12.1-12.6

 

Oh and i have a ground kit.....one from bat-body, one uim-firewall, one tb-body, one timing cover-body. All are 2 ga w gold terminals

 

This issue only applies to 5th gens.

 

your 100% sure of that? Because if so then I need to reevaluate my solution. I havent checked my harness though, that and the ECU are all I have left

 

He's 100% right.

 

IACV will not cause a rough idle (misfire). It only controls idle speed.
If the valve fails to function and is closed the idle speed will default to the throttle body setting, which should be about 550. If it fails open you'll have a very high idle.
The valve only controls air flow which in turn sets idle speed.

 

a simple resistance test for the IACV will tell u if its good or not. Test IACV per how tos

 

Make sure your coilpack connectors are snapped all the way on. It's a long shot, since that would likely affect driveability too, but it's easy enough to check.

 

Check your throttle cable to make sure its not to loose.

 

Check all your hoses, they get brittle and crack really easily. I replaced my valve cover gaskets a few months ago and had to get 3 new hoses because they broke or cracked badly. There are a lot of little hoses connected to the UIM and throttle body. When you took both off did you number each hose and connecter and what it attaches too? Thats what I did and putting everything back together was a breeze. If you didn't, visit one of your friends who has a same year maxima as yours and compare everything in your car to his to make sure you put everything back together properly. My guess is you forgot to plug a hose back in or plugged one of the hoses into the wrong spot, seeing as how this started after you put everything back together.

 

I didnt label....smh...and i also dont have friends around w maximas.....i thought of "test driving" the only one on cl in tyler n check it out.....i could also go to a pick n pull n check out vac routing.....or if someone w a 95 would b awesome n post a pic just under the tb where all the little hoses connect id b much obliged.....ps its not coils, iacv, or maf, and i dont find any vac leaks.....REALLY hoping its not electrical at this point!!

 

Definitely a vac,loose or in a wrong location since when driven all is well.....

 

What he wrote.

There is ample potential for creating a vacuum leak doing this job.

Recheck all the vacuum hoses and breather hoses.

 

ok so i went over this again today checking and replacing more hoses as i went....and i found the issue. It was the egr valve gasket, for some reason it had slipped off the far bolt and was hanging by the front bolt (bolt you can see)....so i got it on there right, put it all back together and what do you kno.....car runs like it should.

I appreciate all the help you all give we with this car...i am limited on knowledge but willing to try and learn whatever! thanks again!!

 

glad you found the problem . I was going to post basically that. when I did my valve covers years ago . I left the EGR tube bolts loose and had exactly that problem . tightened them up and idled perfect after that