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Discussion Starter #1
I have an 08 350z with 33k miles, and have an issue with idle on start up. And this only occurs when the car has reached it's normal operating temp.

What happens is, on start up the rpm rises of course. Then drops to nearly 100-200rpms, like it's about to stall, but doesn't. Then raises back up to it's normal idle of around 300-500rpm, and stabilizes. At time's I would blip the throttle just a tad for insurance, even though I know the car won't stall. But I know it'll drop real low before it picks back up to it's normal idle rpm.

On the other hand, on cold starts I do not have this issue at all.*The car does not have any CEL lights. Car is completely stock.

Any ideas on what may be causing this odd start up idle issue
when the car is in normal operating temp?*I appreciate anyones input!
 

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Have you taken it some place to get a diagnostic readout? Go to a local auto parts store and borrow the OBDII scanner. Maybe you have a vacuum leak. Or it could be worse.
 

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I actuallt had used an obdii reader recently. Nothing came up, also my car doesnt have any CEL's either.
 

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Man, I'd be checking all the connections, connectors, hoses, etc. There has to be one weak link.
 

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hmm, that's a lot of vacuum hoses and connections. I assume first checking the electrical connections or vacuum hoses that relate to the throttle bodies correct?
 

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I have the same exact issue on my vehicle (03 with 75k miles) ive just learned to blip the throttle on warm start ups... also, every so often when i stop at a red light it will also drop in RPMS but thats like 1 in 500 stops its very rare... ive looked at all hoses and only thing i can maybe think is the oil pump is starting to go but this problem has been going on for a while id think the pump would of went already... really like to find and fix for this though....
 

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Sorry for the long bump but I'm having exact same issue as OP. Going to need to take it in soon but I'm wondering if OP ever found the issue and/or solution. Honestly been doing this ever since I bought it, ( 08 with only 9000 miles when purchased). Today was the 1st time the car actually died out cause of the rpm drop. Thanks
 

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No need to apologize - were all here to help ... Looking at this again - check your mass air flow sensor - get a can of MAF cleaner and clean the sensor. Aside from being super inexpensive it something you should do anyways. I can see a vacuum hose coming off and causing the air flow to be unbalanced but if no vac leaks are found couldnt one say the MAF is giving off inaccurate readings?
 

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Have you diconnected the battery lately? If so, your car will idle correctly after a dozen or so warm starts. It will take that long for the ecu to relearn the warm start fuel air mixture. If you have not diconnected the battery I would first try cleaning the MAF sensor with some MAF sensor spray/cleaner. Really not hard to do, as stated. Also besides looking for a loose vacume hose you may want to check your ground cable.
 

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Bumping this because I have a similar issue.

2009 370Z, 60k miles, no real issues and regular maintenance and oil changes.

Complete car noob - don't even know how to change my own oil - so I end up spending the extra bucks on the dealership premiums.

Did some research about a month ago and everyone said throttle bodies, so I took it in and had that done, and didn't have it dip to 100-200 RPMs on start for the past 3 weeks or so until now when it had a really rough idle where it almost died.

Haven't had it die yet, but apparently the TB work didn't fix the issue so now I'm back at square one and stumped.

Car always idles less than 1k RPMs at a stop - not sure if that's relevant.

Love the Z. I know Nissan doesn't have the best quality but I'd keep this thing forever and pristine if I could.
 

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My original post went away??
I'd sure check your cam position sensors.Your car has low miles for one to go.
But,you never know.You will not get a CEL until one goes out completely.
Until then,it will act rough,then go away.Then,get a stall,go away.
It's common for the cam sensors to go around 60---70k miles.
If you replace them(there are 2) get OEM parts,not aftermarket.
 

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I have this same issue on my 08 Z. The RPMs always dip low on a warm start up, it has never stalled out though. It has 95K miles on it at the moment. Cleaning the MAF sensor did not work for me but it hasn't really been an issue.
 

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Check the throttle body. I had the same issue and cleaning my throttle body solved it. Also I cleaned my MAF for same measure. You have to really get in there to get all the crap out. Just make to disconnect the battery and drain all reaming power and disconnect the TPS after that. Then clean the outside and inside on both sides of the TB.
 
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