3.5L V6 "Surges" Around 3.5K RPM and 4K RPM

I picked up my 2016 Tacoma about a week and a half ago and experience a bit of a power surge near 3,500 RPMs and again near 4,000 RPMs while keeping a constant throttle position. I was wondering if anybody else is experiencing this, or if it's just an issue with my specific truck? I was thinking that the Atkinson Cycle and direct and port injection could have something to do with it, but figured I'd check in with all of you to get a little feedback.

Another thing I've experienced and am curious about, is the truck sometimes holds the RPMs up when I shift from first to second gear. It doesn't always do it, but does it often enough that I'd like to see if anybody knows why it does that? I was reading a thread a while back that said the second generation also did this, so I guess it's not a new phenomenon, but it would still be nice to know the logic behind it and to know if there's a way to drive the truck to minimize this.

Other than that, I love the truck! It's a black DCSB OR 4x4 with the manual transmission and has been an absolute joy to drive. I currently have just over 1,500 miles on it, and have loved every minute behind the wheel. My previous daily driver was an E46 BMW, so the Tacoma is quite different, in a pleasant way, to what I'm used to. It seems like there's a lot of good info and people here so I'm definitely looking forward to being a part of this forum!

 

Awesome truck! Welcome to TacomaWorld

I have a TRD OR 4X4 AUTO ... I don't recall any surges and I have about 5500 miles on it already. Yours is still new, so maybe the computer is still learning or maybe a touch of water in the fuel from the last gas station. Hope it works itself out ... and welcome.

 

Most likely the variable valve timing.

 

I feel the same thing also in my manual. It almost feels like a spike in the torque at those rpms.

The problem that I have noticed is a misfire of sorts if I floor it in third gear around 1800 rpms. Power cuts out for a split second then runs fine. Have you noticed this?

 

The 2016 has a 3.5 L? What happened to the 4.0?

 

Nice looking truck. Can't say I have any of those issues with my rig

 

Here is what the torque profile may look like (potentially very similiar 7GR). Notice the small bump in torque just above 3K RPM, and the big bump going up to 4K RPM. If the 2GR's profile is similiar, it could explain what you are feeling.

From: https://www.tacomaworld.com/threads/2016-tacoma-dyno-torque-hp-crve.391512/page-6#post-11149837

Regarding the RPM hold after shifting from 1st to 2nd gear...I am really confused. You have the MT...how can the transmission hold the RPMs at the same (higher) level after you have switched gears and left the clutch out without slipping like mad?

 

I think he's referring to rev hang. The 2nd gen v6 did that, held rpm for a second after taking the foot off the accelerator, and it made the truck kinda tough to shift smoothly at times. Also thanks to that rev hang it liked to bark the tires in 2nd gear if coming off high rpm while shifting anything faster than dead slow.

One way that might confirm similar programming: shift into neutral while rolling any speed over 15 mph and let it drop to idle. The 4.0L would stabilize idle at 1400 rpm, whereas the 2.7L that has zero rev hang tendency will drop to 800 rpm. If the ECM isn't programmed to close the throttle plate all the way during the shift then you won't get the manifold vacuum to drag rpm down as fast.

 

It is completely normal. It is the variable valve timing. It does the intake then exhaust I believe. Honda and others do the same thing. Most familiar with would be Hondas V-Tec. Kind of the same thing. Makes the truck rip when it kicks in huh? I noticed it isn't as noticeable at full throttle but three quarters throttle it come on hard. I love it personally. I think these things are pretty darn fast for what they are. The more miles I put on my truck the better it runs.

 

I feel the same torque spike in my manual trans truck. I have 2500miles on mine. I have noticed that I have no RPM hanging between shifts unless I run it up past 4000 rpm, once they are that high it seems to hang a little between shifts.

It could be that the RPM's are higher so it take longer for the RPM to drop, I'll try and pay more attention to it.

 

I've got about 8k miles on mine and it does the same thing. It reminds me of a 2 stroke dirt bike when it hits the power band. I notice around 3800 RPM and 4400 RPM.

 

This is exactly how i would explain it feeling as well, a power band.

 

Wow! Thanks so much for all of the feedback! Every reply was very helpful, and yes, it feels exactly like hitting the power band on a two stroke. The BMW I just came from was designed with a VANOS system and had a little bit of a power band surge as well, so I had suspicions that it could be the variable valve timing. After seeing the torque profile, it all makes sense and that graph is essentially what I feel in the seat. Once it hits, it definitely gets with it, but I just wish I could have that power all the time. As mentioned earlier in the thread, I do experience this more at 3/4s throttle than WOT. In regards to the RPMs staying high while shifting, the rev hang is what I was referring to.....nothing to do with the transmission, just the RPMs sometimes stay up momentarily with the clutch engaged and no throttle being applied.

 

Agreed about the fact that when those two power bands hit it throws you back a bit in the seat. I wish there was a bigger power band at about the 2000 RPM mark. What is interesting is it does not seem the Automatic guys have this same power band feel. Maybe something to do with the direct gear drive of the Manual vs the Automatic and tq converter? I really know nothing about autos but it just seems interesting that the manuals are the only ones that can feel these torque bands.

 

It stayed in the better generation

Hope you get the issue figured out OP. Considering your truck is new, I'd give it a few weeks before making any determination. The ECU is probably trying to "recognize" your driving habits and is being broke in at the same time.

 

Ahhhh, the thought of a power band starting around 2,000 RPMs has me salivating....what an excellent truck it would be if that were the case. Perhaps the automatics experience less of the effect due to the fact that they're usually pretty close to full throttle if they're going that high up in the RPMs, and when it shifts to the next gear, it doesn't drop below the power band. I don't usually take it to redline when I experience this, so I usually end up below the torque curve for my next gear. I'd be curious to know if they feel the power band while in manual mode at slightly less than full throttle.

I'll put some more miles on the truck and will report back if I notice any differences in the behavior of the truck.

 

Auto here, and I notice the surge of power at exactly 3500 rpm. I just figured it was the VVT opening up. Pretty gutless below 3500, but it rips afterwards!

 

I feel this exactly as described. I have TRD sport DCSB 6M. Almost like a turbo kicks in at 4.5k rpm. Really fun actually.

 

I also have the auto tran and I feel it power surge right around 3500-4000, it puts a smile on my face every time.

 

this !!