Hey folks,

Need some advice here. Have a 2004 5AT G35 Coupe.

Recently, I've noticed that when I start my car throughout the day, the RPM shoots up to 1500 and then it settles down very close to 200 intially and you can feel the engine dying a little and then it climbs back up to 500/600 rpm. Sometimes when it dips to 200 rpm, the engine goes and then I have to restart my car with no problems.

My questions is the why does the RPM spike up and then down so close to 200 RPM that it sometimes gives way and just goes to 0 and the engine dies?

Please help! I'm suspecting my idle, after 20k miles needs adjustment.

-Cuong

 

Do an ECU reset and see if it helps, first.

2nd - it really sounds like a vacuum leak to me.

What work has been done on it recently since this started?

Rick

 

i have the same problem. check your battery connection.

 

have you done any mods to it lately or had it serviced on? You can take it to INFINITI and tell them that your having problems with your idle and they can reset everything for you (should be free).. if not then go to a NISSAN dealer and if its still not free its cheaper to get it done at nissan then infiniti..

I use to see alot of cars with this problem especially after intake mods and the fix just to take it to a dealer where they can readjust everything. or it can be a vacuum leak like rick mentioned but you'll notice a rough low idle if you have a leak.. and it'll ALWAYS be like that at idle not just upon start up.. if its only upon start up take it to a dealer

- Eric

 

Not necessarily - plenum leaks can easily seal themselves back up when the car gets warm and things expand...bolts get tighter and everything...

Rick

 

Problem resolved!

They just replaced the TPS sensor under warranty.

Thank you all that contributed on the replies!

 

Cool...enjoy now!!!

 

So what did they do to fix the problem...... my 6MT stock coupe has a very suttle shake to it.....everytime when the car is at idle........and every now and then you can hear the exhaust spudder..... and about two weeks ago...... I started my car after not driving it one night and it kinda act like it wanted to stall before it rev-ed up........it freaked me out for a second so I let the car warm up without giving it any gas.....after it warmed up..... I decided to rev up it.....well after I let off on the gas and as the rpms came down...... the car acted like it wanted to stall or die.....but it did not.....it just went back to normal idle........ It has not done that again since that day.....but does any have an idea as to what is wrong........ I took my car to the dealership about 6 months ago for the suttle shake problem and the dealership said that there was nothing wrong with the car.....after they hooked up the ECU......they said that everything looked normal......... For some reason, I think that the incident mention above has something to do with the car having those suttle shakes and exhaust spudder.......

 

i had this same exact problem...i took it to my mechanic and he cleaned the throttle body without disconnecting it...after he did this the car was

perfect...he told me if i wanted that i should buy a can of throttle body cleaner, take it off the car and clean it better...so i went home and i did

this...i disconnected the throttle body with the battery disconnected...i hooked it back up and then it started to idle at 1k rpm (this same exact thing

happened to a couple of other members after cleaning)...i think it was because the computer got adapted to the carbon deposits that have been

there for a while and now they are gone...i tried an idle learn but that didnt help...i tried disconnecting the battery and pumped the brakes, i also

disconnected for 12hrs and still no luck...i also hooked up an odbII and it said that the idle was above regular idle...i called the dealer and they said it

would cost me $140 to check it out and if it's computer related then they can reset it or whatever...but im scared that if i do that they're gonna say that i

need to replace the whole throttle body which costs $900...god i hate the dealership...do you guys think the sensors/ecu will eventually adapt? is there

a TSB/recall out for the throttle body? any feedback is appreciated...



edit*: problem solved...i just went to the dealership and they recalibrated the ecu under warranty

 

When I cleaned my throttle body on my old car, the RPMs stayed up for a while, but once all that dirt or spray burns off, probably off of one of the sensors, your RPMs should go down back to normal. I would drive around like nothing is wrong for few days, and see if it goes away. If it still idles high after a week or two, then go to the dealer.

To the people with dipping RPMs, I had the same thing on my G. It took two visits to the dealer, and finally the tech was able to notice the dipping problem, and performed the "Idle relearn" on my car for free, and the car was like new. It's been more than 6 months since, and I notice it slightly again but very rarely, and when I asked the dealer to perform idle relearn again, they came back telling me they didn't notice anything wrong with the idle. The funny thing is, when I got home, I examined my bill, and there it was at the end, recommended service: 30k maintenance and idle relearn. I hate dealers.

 

same EXACT damn thing is happening to my car now... it sucks! people at times think i stalled out when in actuality its my idle that died out the motor lol Im going to take it to my mechanic for him to see whatsup with it... i didnt have a problem with it until he changed my clutch.flywheel. Its a good thing i searched this topic before making a new thread about it lol