I think I've been noticing something similar recently. It has correlated to some extremely hot weather 95+ in the past week or two. Hard to describe but I think it is the same as others have described.
It only seems to occur once fully heat soaked (not during the first 15-20 minutes of driving), on a really hot day, with the AC on. From takeoff it feels as though it has at most about 75 horsepower until the revs build. Letting out the clutch and trying to go it literally feels like nothing is there, like it just falls on it's face. A second or two later it goes like nothing ever happened. Almost like the worst turbo lag you can imagine. Pulling away from a stop light in first there is a very significant throttle lag and then as the RPM's build it rolls on quick and then feels normal. If you've ever ridden an old two stroke motorcycle that doesn't quite have the jets dialed in and has a really snappy power band you get the idea... Continuing on and accelerating through the gears I don't notice it anymore. This occurred maybe 3-5 times over a one week span. It has been very isolated incidences so far. It's annoying but I have no idea what would cause it. Maybe a detail in my useless description will give someone an "A ha!" moment and help narrow in on a potential cause for the rest of us. My thought was perhaps a throttle position sensor but the temperature dependence had me thinking it was maybe ECU related and resulting from air density/engine load (AC)/fuel mix/etc...?

 

i've had my 6MT sedan for almost 8 years. it has always been soft on power down low in the RPM range. it is a bit worse in hot / heat soaked conditions, but nevertheless the weak bottom end has been constant. resetting the ECU sorta helps (maybe) for a short while, but over time the "lag-iness"returns.

at this point i'm considering it normal for the VQ when hooked up to a 6MT. when the dealer looked into it i was told the same - no codes thrown, no known issues. just a characteristic of our drivetrain.

once i get up to ~2500-3000rpms the engine really starts to pick up and by 3500rpm it pulls strong. like above post mentioned, almost like a 2-stroke coming on cam. this is most noticeable in gears 1-2-3.

i'm not saying that everyone in this thread has nothing to worry about, but some folks may just need to get used to the way power is delivered with our vehicles.

i drove my bro-in-laws 2.0T genesis coupe last week, and in certain aspects the VQ exhibits similar lag to the turbo in that car - except that torque does come on earlier and stronger with the genesis while the VQ pulls much harder after 4000rpm.

 

I don't disagree with you. And that's the best argument for short rear gears or a LW flywheel.

Since the latter means added NVH, and I've already gone through with the effort on the gears... I advise gears.

 

That's a fair assessment. No one would ever call that motor "torque-y". The experience I'm trying to describe makes that normal lack of bottom end seem downright powerful though. The first time it happened I literally thought the car died. It completely fell on its face just as it started to roll and then just picked up and took off like nothing ever happened.
Picture your "soft on power down low" sensation at takeoff and then remove 90% of that power for 1-2 seconds. It's disheartening to say the least.

 

I'm right with you, it's very disappointing when it happens, and extremely noticable. Glad I'm not the only one that experiences it. Also have to reference the 2 prominent thoughts: throttle sensor, or fuel at some point...be it pump, injectors, or any components therein.

 

Or even possibly belt/pulley issues since it seems more prevalent with ac on and warmer temps

 

Everyone this dead pedal happens with, do you drive with your traction off?

 

I have the same experience with a 2015 Q40, its a heat soak and iat issue. The ecu has to pull timing based on iat to protect from pre detonation. Never happens during cool weather. Im going with a cold air intake and some heat shielding to help. Also, when accelerating from low speed or standing start, go half throttle for a split second before flooring it, the motor will respond better instead of bogging down.

 

Hey have you fixed this issue? I have been looking everywhere and I cant find an answer to this. its really frustrating, just like everyone else, I have been cleaning the tbs, changed sparked plugs and so on, the car is a 6mt and whenever I accelerate under 3000rpms, the thing struggles like crazy, and over 3000rpms, thing just shoots up like a rocket.

 

its normal. Keep rpm above. Problem solved.

 

it's not normal at all. There is a problem. Dead pedal in the car like it's dying isn't normal. No offense, but folks that jump in with these sorta comments aren't helping the few here that feel it, know it's a very real, and frustrating problem.

 

the real fix is a tune.

 

YES IT IS, and these people posting nonsense comments are no help whatsoever

 

I too have felt that issue, and like others have said, TB cleaning, spark plugs, etc.. doesn't help. It happened fairly often too.
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​​​​​​Now I am unsure if it still happens. If it does, it's definitely nowhere near as dramatic. I do have a tune, can't really pinpoint that as the time it got better, but it must be.

 

I believe I notice it with my g37 but never on my g35, I just thought it was the VVEL "kicking in"