Okay this refers back to a post I made a few months earlier regarding launching in 1st gear.

https://www.myg37.com/forums/g37-cou...ht=accelerator

This problem never really went away, it just happens randomly. At first, I thought it'd occur after driving for long durations, but the other day during work I went on a quick food run about 4 miles away and it started happening on the way back (probably at about the 6th mile or so).

I made an assumption from the previous thread that the problem was my clutch, but now I know that's not it. I think it's the accelerator that's causing the problem, particularly when I'm at the bottom of the RPM range (i.e. when I'm at a stop). So when I'm sitting still and about to go, I'll put the shifter into 1st and gently press the accelerator (I probably press it in about half an inch and keep it there). At the same time, I'll slowly release my clutch up to the catch point and then keep it there. This is hard to describe, but my RPM's go from about 1200, then dips suddenly to about 700, then slowly rises to about 1000, then jolts up quickly to 1400 (during this time I feel like I'm in a rocking chair). After about 1400, then everything seems fine, and shifting to the other gears goes smoothly (of course, I don't really fall into the low 1000's again unless I come to a stop). This happens at every subsequent stop.

Not sure if pulling over, turning the car off, then turning it back on would help (nor have I tried). Usually I just get to my destination, stay there for at least half an hour or more, and when I get back to my car, everything is fine again. Sometimes I can get through an entire excursion without this happening. But about 10-20% of the time, I experience this issue.

Sorry, I can't seem to find the words to describe this more clearly. I hope that the dealer can take a look at this for me, but I'm not sure how I'll describe this other than what I just typed above. If this occurs while I'm near the dealership, I plan on just bringing it in and keeping my car on so a tech can drive it around and see what I'm talking about.

Anyway, same question as before. Has anyone experienced anything like this before?

 

sounds like either a glitch with the foot pedal and its sensor or one or both of the throttle bodies motors might be glitchy where at a very low throtte opening it gets an electrical glitch which jerks the throttle body plates a bit. anything past this might have to do with the VVEL system and the valves are causing the jerkyness since they act as throttle bodies in the VVEL system.

I think the dealer should be able to plug in the consult and log what is actually happening during that situation. even with a innovative OT-1 logger you would be able to log that and see any weird throttle movement or VVEL system jerks. if the ecu see's it then you would see it too.

 

I'll try to regurgitate what you just said to the dealer to the best of my ability haha. Thanks for the input.

 

My first 09 6MT had an issue where it felt like the clutch was bouncing back and forth when starting off from a dead stop (it had < 6K miles on it) and I was going to ask the dealer about this but that car was totaled in October about a week before I went in for 6K service, the replacement 6MT doesn't do this (but only has 300 miles on it).

 

Chase, the symptoms sound like heat soak.

It sounds like it happens anytime you come to a stop after everything under the hood gets to full operating temperature. That's not really normal with a stock intake system...

I'd say:

1. reset ECU
2. check air filters

If that doesn't fix, dealer it is...

 

Possibly. The only thing is that sometimes it'll happen like 45 minutes into my drive. The car should've been at full operating temperature way before that, and it didn't exhibit those symptoms then.

I'll try resetting the ECU later. As far as the air filters, I'm at 22K, so I guess it's time to swap them out...?

 

Seriously?

Air filters are supposed to be swapped out every 15k miles, maybe even sooner depending on your driving conditions.

 

^^you serious? lol im at 28k and havent swapped it out yet

 

That's the recommended interval, but it varies depending on driving conditions. I just came back from the dealership and they said my filter is a bit dusty but still looks good. I'll probably switch it out at my next oil change.

Anyway, the dealer reset my ECU and they said if things aren't better, bring it in next time and they might have to swap out some component in my car (forgot what it's called, some sort of controller).

 

Did the problem go away? I'm beginning to notice this every once in awhile when I start in 1st gear also. It exactly as you described with the rocking motion. Very awkward because one moment its a smooth acceleration than randomly theres this rocky motion as if I'm flooring it in first.

 

Idle controller?
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Perhaps. Regardless, the ECU reset seemed to have helped. I haven't experienced any problems thus far (*knock on wood*). Try that and see if it helps.

 

Ok thanks I'll Try resetting and see what the dealer does if it comes back before my next oil change.

 

Mine does that too but I just thought it was a Nissan thing. I've had nothing but Nissans for the past 20 years and they all did it except for the '79 280zx.

 

Thats weird so are you saying you experience this all the time when starting in first gear?