Me too
 

I've had this same exact issue for about 3 months. I bought the car in February and the issue reared its head in May. I have a 2010 6MT w/ Sp pkg.

For about the first 15min after starting the car, acceleration is fine and very responsive. Afterwards, no matter what gear you're in it bogs down for 2-3 seconds when you hit the gas. It doesn't matter if you floor it or even moderately press the gas. Oil temp, toggling VDC on/off, having Smode on/off; none of that matters either. I agree that they all play a role in throttle response but this issue is completely different, since none of those items previously mentioned cause the car to "fall flat on its face".

Nissan dealership will tell you that it's an oil temp issue and recommend an oil cooler. They will also tell you that Nismo is developing an oil cooler that you can buy. Why should I have to buy additional parts to fix an apparent problem from the factory????

^ Exactly the same issues I'm having. I don't think it's an oil temp issue because lately I notice it happening when oil temps barely touch 180F. Plus, it comes and goes. One minute the car bolts when I quickly tap the pedal in 2nd gear, and the next minute I'm flooring it and it feels like the throttle is barely opening at 20%.

Some of these issues sound like the posts about the brake switch sticking and causing the ECU to limit throttle to 15% - maybe you could get an OBD gauge or recorder and see what it reports when you have the problem.

I did this. But every time that I'm driving around with my computer hooked up, the problem won't show itself (at least not near the extreme that it sometimes does). Of course it did it all weekend, while I was out of town. Just my luck. I'll keep trying and post results for all.

Does anyone know a lot about O2 sensors? I read this article: OXYGEN SENSORS and it makes sense. Is this accurate? Does it apply to our car? If so, I am going to record just O2 sensor data this evening, and try to post it tomorrow. Even if the problem doesn't show itself today, maybe it'll be a good baseline. Can anyone confirm how many O2 sensors I should expect to see?

o2 sensors have nothing to do with this problem, or much of anything in all reality, except pollution control.

Well, a primary O2 sensor being out of whack could cause your fuel trims to be pretty extreme. That would lead to kind of a "dead" feeling every time you crossed over from closed to open loop fuel operation.

But if it were that bad, your ECU would let you know about it (service engine light).

Secondary O2 sensors have no bearing on fueling or how the car runs. They are the "rear" two sensors downstream from the catalytic converters - one per bank.

So anyone talked to a dealer about this yet?

KillerBee370 also mentioned his tuner fixed this (see page 13)....
What was the fix...??

while yes, in theory, you are correct, but ive never seen a sensor cause such havoc. for all intents and purposes, the o2 sensors are mere monitors and even bad ones wont cause fuel trims to change performance, noticeable anyway. but who knows, this car has proven to be a very weird car already in other ways.

Agreed, however, if the ECU algorithm is jacked, I think it could cause exactly that. I just realized my OBD software won't let me save data, so I can't post my drive =( Will keep looking for other software.

Has anyone had this problem in the evenings? Or mostly in the day time?

... Yes. I got blown off. But then again, this dealer is notorious for crappy service. This time I am trying to bring them hard evidence of something, and also going to address it as a safety concern. If that doesn't go anywhere (which I kind of suspect it won't), I will move up the chain.

from what has been documented ever since electronic throttles became instituted in just about everything, the real culprit is the time it takes for voltage to be sent from pedal to the ecu to the throttle body to the TPS to the ecu to the injectors, so on and so forth. ET's add extra time to the mix unlike cables that are as close to instant as you can get.

this same idea can be seen clear as day if you hook a volt meter or gauge to your battery and start the car. the meter will read 13.5-7 or so. now have someone rev the motor, and watch the meter or gauge go up to 14.2-7. the jump isn't instant, it climbs, not slowly, but slower than instantly. the increased rpms spin the electromagnets in side the alternator faster, but voltage still has to be transferred.

it seems like this sprint thingy speeds up the process by increasing voltage, making the lag less noticeable.

That's not really what the issue many of us are describing, though. Of course there's going to be a signal delay, but with this, the engine responds, bogs for 2-3 seconds, then surges forward.

What would happen to me is I'd give the car throttle and initially get put back in my seat, only for the car to STOP accelerating, bog for 2-3 seconds, all while lunging me forward because I was bracing for acceleration... then all of a sudden it'd violently take off again. It felt more like fuel starvation or TC/VDC cutting power more than anything else, although there's no evidence to suggest that's the case. That's what it feels like, though.

Bottom line is I solved the problem... I bought a new car. :/

^^sucks you had to give up the car to fix the issue.

For whatever it's worth, I haven't done any performance mods yet. The car is bone stock with this acceleration issue. I'm going to be giving it to Nissan for a couple days this week so they can troubleshoot it. If they can't do anything with it and no one has found a fix on this site by then, I'll press on with new intakes and possibly a tune. If nothing by then, I'll seriously consider going the route the previous poster has just taken.

gotcha, how do you like the 'stang? things beast and a half i hear.

I get what you describe real bad in first gear, even before the vdc would, i assume, kick in, as well as low rpm 2nd and 3rd.

I had intakes, exhaust, and a tune and it didn't make a difference at all.

I love it. It's an amazing car. :tup:

I don't have delay like most here have, mine just feels like it does not have a sense of urgency when I step on the gas. The power is there, but it does feel like it is because the power does not come on instantly. The car is going to Seb at SpecialtyZ next wednesday for a full tune so I hope he can work on the throttle map and perk it up a bit.

I look forward to seeing the results of the tune!

that is probably the most reliable thing to do. that way everything works in harmony without any tom-foolery.

I drove around earlier and i don't think i have a problem at all when the vdc is off, instant power on demand, but a cable throttle i would still prefer.

You do know electricity travels at roughly C (the speed of light - 3 MILLION meters per SECOND)... and most processors these days process data in fractions of milliseconds.

Exactly. It is almost completely unresponsive for 2 or so seconds. The thing that I don't get is that it's very intermittent. Sometimes it's just a little unresponsive for that time, other times it almost doesn't do anything at all, then sometimes it's just fine! Hopefully you'll have better luck dealing with them! Please let us know if you do. I've been brushed off.

I was thinking maybe it was some sort of torque management, but there's no way it could be that considering how violently it lays down the power once it decides to go.

Anyways, I don't have to worry about it anymore since I sold the Z. :/

I certainly hope you guys can come to a solution. I know just how annoying (and dangerous) it can be. :shakes head:

yep you're right, but step motors, ecu's, sensors, and relays dont work that fast. the step motors in the throttle dont snap closed to fully open at the speed of light - 3 million meters per second, it is gradual, as is the depression of the gas pedal.

3-5 secs is a long time... r u sure thats the right amount of delay?

Are some of you kidding me? 2 sec delay? Geez. That's right, there is a 2 sec delay in a car that runs 13 sec in the quarter mile.

The throttle plates on the VHR are fully open during normal operation - the VVEL actually throttles the engine by adjusting lift.

For me that's slightly exaggerated. It's more like 2 seconds (though I can't speak for everybody). However, I have been in situations where it feels like an eternity!

So odd... I was doing a bunch of 0-60 runs last night to get my E-Tune done and didn't notice any real lag (maybe under half a second). I'm wondering if its tied to specific ECU's? I'm using the 1EA4B ECU.

Its no joke man. Its not a throttle response delay... throttle responds fine but immediately after gassing it the car bogs for 2-3 seconds before violently surging ahead. It feels like VDC is coming on and cutting power almost immediately after you get on the throttle. It happens anywhere below 4,000 rpm.

With outside temps getting cooler I am not experiencing this problem as often compared to the summer temps that exceed 100F everyday.

There was once instance where I made a brief stop at Walgreens, went back out, started it up, and responsiveness came back. Try briefly shutting off the car and starting it back up to see if the problem goes away. I think it resolved the issue momentarily.

Does anyone experience jerking feeling (versus smooth and progressive) when gradually pressing the throttle down to the floor? It can be easily tested in 3rd gear. When it happens, giving it more gas in 1st feels like rough clutch engagement. Then in 2nd I quickly floor it briefly, and it doesn't push me back in the seat. It's like I went from 2nd to 6th.

I think we need to keep pouring in complaints to NNA.

You are driving a high revving V6, it's going to feel sluggish at the low RPM. My Prius felt stronger than my Z down low, but that is definitely not the case as verified by my datalogger

PERFECT short description.

Again.. it's *NOT* that. When the car is "normal" it's a linear feeling. With this problem, it's not linear in the least bit. You go from starting to accelerate, to *NO* power. Zip, nada, nothing... to an explosion. Like previously stated, it almost feels like VDC is kicking on for a sec.

I have been experiencing this problem as well, but it seems like its related to heat because the car doesnt do it when its 180 oil temp or below.

It's not that AT ALL.

You get on the throttle... the car responds instantly and takes off, only to immediately cut power, throw you forward in your seat (since you're bracing for acceleration), bog for a good 2-3 seconds, then all of a sudden violently take off again. It's got nothing to do with the fact that this is a high-revving V6.

I agree as well. I can't replicate the problem at night. I won't know what it's like during cooler weather for another month or 2.

if the engine actually stops and sounds quiet, its fuel cut due to starvtion.

oil temp doesnt effect the car as much as you think. i have a datalogger, car can accelerate just as fast at 270 oil temp vs 220

The engine doesn't cut. It's still running. It just feels like a fuel starvation event... that's the best way I can describe it.

All I know is some cars experience this, some don't. For those of us that do (or did) it's very annoying and sometimes dangerous.

no ****! i didnt know that, im not familiar with new VQ's much at all, hardly ever have to work on them. the way i was describing the actions were just generalized concepts used in "most" electronic throttle cars. im glad you enlightened me!

Somebody needs to log the throttle plate position while this is happening.

I know on the Evo X, you can log the accelerator position separate from TPS - lets you know what the ECU is actually doing to limit throttle.

I'm guessing this won't tell you anything if what I've learned about the VVEL system is true - you'd have to be logging some other value that tells you how much valve lift the ECU is requesting of the VVEL system.

Do you know of an affordable system that will allow me to do this?