hey guys well when i am driving MOST of the time....when i come to a stop it idles at 650rpm which is right.....well every once in while when i come to a stop it will idle at 1000 and stay there....what can make this happen....if i turn the car off and back on it will idle normal at 650....what can i do to fix this...once it starts idling at 1000 it will stay like that till i turn the car off and back on.....

oh yea its a 1996 nissan maxima with a VQ30DE

 

lean your ICAV, MAF, and TB

 

So it happens when you come to a stop, how specifically? I used to have that similar problem, only it would travel all the way up to 1500 rpm, and was usual tarter coming off the fwy. I did just what the above post stated, and made sure I corrected all the codes on my car, and (due to a code I've had for almost 3 years) made sure all my air hoses were connected the right way. Honestly, it was the reason I had that high idle at every stop.

 

ok here it is more specific....i turn the car on....it idles properly at 800 in park....switch to D and it idles at 650 i drive around for a while and do a few stops it still idles at 650 then after a while i will stop at a set of lights then bingo...it idles at 1000 and 1500 in D and it stays like that at every stop.....then if i quickly turn the car off and back on it idles properly back at 650 in D....

 

sounds like a dirty IAC to me

 

yep, just do some cleaning, maf, iac, air filter and see what happens.

 

dont forget to clean the IAC tube from the airbox to the IACV itself, mine was dirty( from an over oiled K&N) and it would only idle once in a while

 

can some post up a pic of the IAC and what ever else i need to clean....im still new to the VQ30DE and have no idea on what i need to clean

 

http://forums.maxima.org/4th-generat...on-maxima.html

 

thanks mate

 

http://forums.maxima.org/4th-generat...g-dummies.html

 

Just to be sure, you don't have any CEL codes on do you? Like I said, even after cleaning I used to have the same problem until I switched I over two incorrectly installed hoses that lead to the manifold and all the other breathing hose entries. Just want to make sure you're covering all your bases man. Best of luck!

 

what are CEL codes....and my car hasnt done it now for 2 days....wierd...its like grimlins are working in my engine bay....if it get worse i will pursue to fix it.....

 

CEL = Check Engine Light. For any codes your car might have with the emissions.

Let's hope it was jus a fluke man and good luck again!

 

thanks man....yea hasnt done since then oh well...

 

look your max is automatic
but sounds like my 5spds have
just clean your IACV your TB
and if is possible
change your MAF
i change my MAF
and my problem dissapear
completly

 

well took some time this morning and cleaned the iacv and tb and its still doing the same problem i thought it was fixed idled better and more smooth....took it for a short drive it was ok....took it on the hightway came to a stop and problem came back.....stayed at 990 rpm in drive and 1400 in park......turned the car off and back on and it was fine again.....errrrr

 

ok so now that it did it again...i went under the ood to see if there are any unusual noises coming from the iavc where the big plug goes there was a loud ticking sound so i unplugged that and now my car is working fine...any explainations?

 

ok so now that it did it again...i went under the ood to see if there are any unusual noises coming from the iavc where the big plug goes there was a loud ticking sound so i unplugged that and now my car is working fine...any explainations? took it for another long drive down a highway and around my suburb and nothing seems to be wrong....i will replace that sensor when i get a chance....because i dont like knowing there are things unplugged but why would this be ticking when plugged in it almost sounds like its trying to open and close...

 

this is the plug i disconnected that was making noise....

 

well i had to plug it back in now because i waited for a while went to start the car and it started funny but when i plugged it back in it was fine....err this high idle is shi*tting me

 

so does anyone have any idea's....so here is a what i have done and the symptoms that i am currently having....

What i have done:
Cleaned throttle body new gasket installed
Cleaned IACV new gasket installed

Symptoms:
Intermittent High Idle....
mainly after i drive on the highway and sometime just around town i will come to a stop and my idle will sit at 1000 in D and 1400 in P.....if i turn the car off and back on the idle will set back to normal.....i also noticed on high idle my IACV clicks aswell

..... **also if that is on high idle if i unplug the TPS and plug it back in will reset the idle aswell just like turning the car on and off**

all i can think off is either
Bad TPS
Bad IACV

what are your thoughts???

 

I would start by getting your base idle readjusted.

 

i have readjusted the base idle aswell after i put everything back together...

 

Im talking about a base idle relearn with the consult tool that dealers use.

 

i also checked my car to see if it is cold starting fine and it is.....once it gets warm it drops down to normal idle.......drive around for a while its fine....then take it on the highway and come to a stop and it idles at 1000 in D....this is becoming very annoying

 

could a MAF cause this???

 

how can i get this done???? do i have to take it to a dealer??

 

Got a vacuum leak?

 

if i had a vacuum leak it would be constant and not intermittent......still cant find the cause for this

 

I would check the high idle cam. When I cleaned my IACV, I had a similar problem. See if the plunger is moving out when the engine gets warm. If it doesnt, the throttle is still on the high idle cam.
I eventually got a new thermal element and the problem went away for good. Here is my thread if it helps.
http://forums.maxima.org/4th-generat...ng-tb-iac.html

 

i have checked my thermal element and its moving in and out like it should.....hmmm....but i dont have any idea on how its suppose to move....i.e. when its warm its meant to be at what position and at dead cold what position is it meant to be at????

 

well i just drove the car hoping it would go into high idle...well guess what it did and i think i am very close to solving it.....i opened the hood and i pushed on the high idle cam not with much force but the idle went back down to normal...but the plunger is moving so i dont think there is anything wrong with it..but i think it may need adjusting.....are these adjustable so it can move back just a tad bit....i think i need mine moved just a tad bit back...maybe something like 0.5mm

 

seems like my throttle body has been replaced or overhauled before because it looks fairly new still....the car has 240,000kms on it....so maybe it needs adjusting....i will try to adjust this and see if this does the trick...you can only cross fingers...

 

i see there is a screw with a nut on the plunger end....can i adjust this?

 

also another question....i been looking at the coolant bypass mod....if i do this what do i do to the high idle cam....can i adjust it to stay the same on the low idle position???? can this mod fix my problem???

 

I dont know about the mod. Wondered that myself. You would have to adjust the cam so it is not on the cold portion.
The little screw is adustable. The plunger moves a significant amount, at least 1/2 an inch IIRC, maybe more. I put a space between the screw and the plunger to adjust mine out as far as I could before I got a new one.
Good luck!
cold, it is all the way in, hot it is all the way out. Mine only moved about an 1/8 of an inch when bad.

 

yea i think mine is trying to move all the way out but the screw is stopping it from moving...im going to try adjusting it tonight and see if that does anything....if not looks like i will be up for a new plunger....

 

ok lets see if this has fixed it...i didnt want to play with the plunger as it is working correctly its coming all the way out when warm and all the way in when cold....here is what i have done and my idle is alot better...drops down quicker when i come to a stop...

got home since the car was warmed up i done this

turned the car off
unplugged TPS
started the car
adjusted idle again just make sure it was correct
turned car off
plugged TPS back in
Started car
everything was ok but IAVC was clicking so i did what i was going to do anyway
turn car off and put in the "on" position
turned the ecu to diag mode
"no codes showed up check engine light stayed off"
turned it back to normal mode
started car
no more clicking from the IAVC

idles more smoothly drops down quicker...but i am still not convinced...if this doesnt do it then i will adjust the plunger screw

 

nope not fixed....i am starting to think it got to be the thermo valve not opening all the way because when it did it again i pushed on the high idle cam and my idle went back down and stayed....maybe just needs a bit of an adjustment...