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Start Up, Then Idle Drops

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Old 05-06-2013, 04:30 PM
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~Lefty~
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Start Up, Then Idle Drops

Anybody experience this? I start the car after using it a few times throughout the day (runs fine), and it revs up like normal, then drops way below normal idle speed and almost stalls, then goes back up to normal idle speed. The car then doesn't seem like it's running right. RPM's seem a tad slower and it definitely doesn't sound as crisp and clean as the 3.7L normally does. It almost happens when the car has been heatsoaked. I'm thinking maybe the throttle bodies need cleaned. This happens randomly, I can't seem to find any consistency with it. Open to other suggestions as well...

Car is 7AT with 29,000 miles.
Old 05-06-2013, 06:14 PM
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tristanbane
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Whoa I thought I was the only one getting this problem.
The difference is, I have a 6MT so I don't think it's the transmission, then...?
I got a new master cylinder so shouldn't be that.

It's probably the engine :\ It started happening after my last oil change, which coincidentally was the first time I had it done by a shop (I was in a hurry before a long trip).... I asked them about it but they had no idea -_- I think I'm just gonna go back to doing it on my own to make sure the oil is good.
Old 05-06-2013, 07:49 PM
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Redline37
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Most likely you need to clean your throttle bodies
Old 05-07-2013, 02:12 PM
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keraxis
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Few possible things

Throttle body dirty, o2 sensor dirty (should throw a code but ive seen them not) or a vacuum leak. Rubber changes alittle as it heats up or gets cold so this could be it if there was a small leak that gets worse as your rubber becomes more malleable.
Old 05-07-2013, 02:19 PM
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IPL 370GT
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Throttle bodies shouldn't be that dirty at 29,000. Check for leaks and pull filters. Check to make sure something isn't blocking the intake or filters. perform a ECU reset and see if that corrects the issue. https://www.myg37.com/forums/d-i-y-i...isconnect.html

If you clean the throttle bodies, clean the maf at the same time. You can find DIY on this forum and the370z.
https://www.myg37.com/forums/d-i-y-i...le-bodies.html

At 29,000 miles... isn't the car under warrant?
Old 05-07-2013, 02:49 PM
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~Lefty~
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Originally Posted by IPL 370GT
Throttle bodies shouldn't be that dirty at 29,000. Check for leaks and pull filters. Check to make sure something isn't blocking the intake or filters. perform a ECU reset and see if that corrects the issue. https://www.myg37.com/forums/d-i-y-i...isconnect.html

If you clean the throttle bodies, clean the maf at the same time. You can find DIY on this forum and the370z.
https://www.myg37.com/forums/d-i-y-i...le-bodies.html

At 29,000 miles... isn't the car under warrant?
Yea, it's under warranty. Usually my dealership is pretty good, but when I told them about this issue they were like "normally the throttle bodies need cleaned bla bla, and we'd charge you because this is considered a maint. item"

Old 05-07-2013, 02:59 PM
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nukee26
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Originally Posted by IPL 370GT
Throttle bodies shouldn't be that dirty at 29,000. Check for leaks and pull filters. Check to make sure something isn't blocking the intake or filters. perform a ECU reset and see if that corrects the issue. https://www.myg37.com/forums/d-i-y-i...isconnect.html

If you clean the throttle bodies, clean the maf at the same time. You can find DIY on this forum and the370z.
https://www.myg37.com/forums/d-i-y-i...le-bodies.html

At 29,000 miles... isn't the car under warrant?
Eh, I cleaned mine at about 42,000 and they were pretty bad, so 29k might not be horrible but still enough to at least give it a shot. Solved the RPM dip at idle for me.
Old 05-07-2013, 08:46 PM
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~Lefty~
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I cleaned em' out - they were pretty dirty to be honest. A little more than I expected, but not too much build up. I also replaced the air filters.

Do I need to do a relearn of anything? I didn't unplug the throttle bodies...
Old 05-08-2013, 11:48 AM
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tristanbane
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Originally Posted by ~Lefty~
I cleaned em' out - they were pretty dirty to be honest. A little more than I expected, but not too much build up. I also replaced the air filters.

Do I need to do a relearn of anything? I didn't unplug the throttle bodies...
Do you still have the issue?
Old 05-08-2013, 02:58 PM
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~Lefty~
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Originally Posted by tristanbane
Do you still have the issue?
I don't want to say for sure yet. I want to give it a few more days just to make sure, but it sounds like it's running better.
Old 05-08-2013, 10:08 PM
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tristanbane
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Originally Posted by ~Lefty~
I don't want to say for sure yet. I want to give it a few more days just to make sure, but it sounds like it's running better.
Alright haha good luck
I'm probably gonna take my car in soon to get it checked out.
It's a little funny because whenever it happens, I habitually wiggle the shift **** and it comes back up (not that it's the solution... but I just got this habit hahah) as if the car was nodding off and I woke it back up like "HEY! get ready!"
Old 05-10-2013, 06:53 PM
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EnviedG35
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I kinda had a recent issue with this. Mine only occurred on a cold start up however. Car would start right up....high idle...then stumble...then go right back up. It started doing it about the time i switched gasoline brands. Ive always been an Exxon guy. I started using chevron and thats when the stumble started happening. The other day after work i filled up with a tank of Exxon. The next morning i started the car up...low and behold, no stumble and it hasnt done it since.
Old 05-10-2013, 10:25 PM
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~Lefty~
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Did the successful reset and it seems to be running better. We'll give it a few more weeks.
Old 05-10-2013, 11:03 PM
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iGGy37S
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Isnt taking the Throttle Body off and cleaning the butterfly valve going to mess up the timing of the intake? Car will run like crap? Correct me if I am wrong...

I have had this issue as well, car will dip bellow a certain RPM and will come back up. I want to clean my TB and do an ECU reset right after, but afraid to mess up the timing of the intake.

Feedback guys?
Old 05-10-2013, 11:35 PM
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tomro99
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had the same issue. took it to the dealer and they reset the ecu. didnt happen again after


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