Attn 6 MT OWNERS (again)

OK reawakening my old thread. Dealing with ‘22 Tacoma Sport 4x4 6 cyl 6 MT. stutter between 1500 and 2600 RPM all gears not lugging. I am assuming others have had this issue. Has anyone else approached the dealer on this? I have to no avail. Pretty sure it’s getting worse. No CEL. Nothing shows on diagnostic scope.

 

sounds like awfully low RPM range for this engine, have you tried test driving another? Start there.

 

2nd gen 6sp owner here

my assumption is the 3.5L vs the 4.0L

I drove a few 3rd gens one was 6spd. I think i felt what you are describing and it certainly felt like lugging.
the 4.0 doesn't mind accelerating from 1,300rpm.
That 3.5 did not seem to be happy under 2,000rpm.
I pulled my small boat (maybe one ton) with the 3rd gen and it was not even comparable my 2nd gen.

two different engines. one needs to rev for decent torque, one not so much.
one gets much better fuel mileage with no load, one is a bit of a gas hog.

remember, the 2GR was not designed as a truck motor, it is a great motor, but it is NOT a truck motor. The consumers general do not need a truck motor in this little truck. That is why the third gen got an efficient minivan motor instead of a grunty gas hog 4.0.

have you driven someone else's 3rd gen MT, to compare it to your truck?

i don't think an online discussion is going to help you resolve this.

 

The 3.5 likes and is happier in higher RPMs. I had to adjust to revving higher.

The stutter you experience I have experienced as well, especially on hills. Flat, i do not see an issue. I was expecting torque to be active at low rpms (1500-2500). It is not, with this engine. The OTT tune helps but the low end balls you expect are not there, its there closer to 3000rpm.

 

Sorry, but mine has had no significant issues from 1k and up. Sure it is not V8 torque down there, but it has never had a problem keeping up with or accelerating away from traffic.

Just in case, here is a driving around vid that I made a while back:

https://www.youtube.com/watch?v=83Y07IO7llo

I have a few more.

Just noting that I am tuned, which is significant, but even stock keeping up with traffic down low was not a problem. The issue was that it did not feel right in many categories.

 

I don't know if this is what you're experiencing but I noticed that since I changed the MT and differentials to Redline (from Amsoil), I have a noticeable lugging/jerking when accelerating. The truck will be in gear and it'll happen between 35 and 45 mph. It doesn't happen all the time though but I have noticed increased frequency

 

I haven't noted any driveability issues with my 22.

 

My 2021 does that. Ignition retard ? try high test/

It doesn't bother me. If it did, I would get a truck with a slush box and never know.

 

I have tried anything you can imagine.

I even did my own tune disabling Atkison and ACIS, tweaking VVT in all sort of ways, changing ignition timing, MAF tables, etc.

However, after 12 months and almost going insane, I found what helped the most are the following changes:

• Switch to premium fuel (you need to run 2 tanks for everything to adjust in all conditions)
• Using VFTune, reduce intake valve advance at high load from 2000 to 3000 rpm to a max of 65 degrees of advance, preferably 60.

The truck is much better, but still crap compared to any other normal manual transmission car.

After a lot of back and forth with VFTune I have concluded the main issue with this engine is that the ECU tries to be too aggressive when doing timing advance. The way our trucks work is that the ECU tries to advance timing as much as it possibly can, until the "knock feedback" value reports the engine is about to knock. "knock feedback" is reported from the ECU in realtime, and there is another parameter to store (learn) the correct timing advance based on knock. With this method, the ECU always tries to be on the absolute edge of knocking, and when it does start to knock it retards timing aggressively and immediately and is when we feel the engine "failing" or studdering.

Even if we change the timing tables via VFTune, the truck will still try to advance timing to the "max allowed". One option is to reduce timing on the "max allowed" table but then you would be giving up power in conditions where more advance could be applied. I have not tried this yet.

If VFTune provided a way to set a target value and a "danger" value for the knock feedback we could set it at a more conservative target and it would probably solve our issue because the engine would not be retarding timing aggressively when it is on the absolute edge of knocking.

 

This^

The lugging feeling is likely due to, well, lugging of the engine. There is not much power down low you may have heard (somewhere).

Know your engine. The power curve graph will give you insight into the power available across the rev range. Your current speed, the slope, gear, your foot, etc. are variables that impact the power needs /requirements of your truck. You have gears for a reason. If you operate outside of the operating range for each gear, you do not get a happy outcome. The advantage of the Manual gearbox is that you can control the gears and not leave it to programming.

Tacos are not light vehicles - do not expect them to move as such...

I see some people with manuals hesitate to shift when they should be doing so. Is it too inconvenient? (laziness?). This is how we end-up with automatics.

 

Ahhh.. So that's what happened. ;-)

 

This is how mine is with 87 octane. With 93 octane, it’s a likable engine.

 

Yeah, it depends as well on elevation, ambient temp and humidity. Where are you located? I am in South FL

 

near sea level, South Carolina. And it’s worse in the summer.

 

It's not a diesel, rev that thing

 

>stopped on on ramp
>traffic clears
>throttle, feather clutch, begin to accelerate.
>truck pulls to 2200rpm
>continue applying throttle
>feel yourself pushed forward in your seat by the nasty torque dip
>continue applying throttle
>engine rpm climbs sluggishly to 2500rpm
>torque suddenly reappears
>be pushed slightly back into the seat
>continue applying throttle
>notice vehicle approaching in rear view mirror
>engine rpm climbs to 3500rpm
>feel yourself pushed forward in your seat by the nasty torque dip
>continue apllying throttle
>engine rpm climbs sluggishly to 3800rpm
>torque suddenly reappears
>feel yourself pushed slightly bsck in your seat
>continue applying throttle
>hit 5200rpm
>shift
>Repeat in 2nd
>repeat in 3rd
>repeat in 4th
>approaching speed of traffic now

Many such cases.

For the past two weeks I have been almost violently thrown forward in my seat seemingly by an ignition cut when pulling out of my driveway. Air temps been in the mid 70s with high humidity. It has occurred every single morning after first starting my truck. No codes, no cel, no warning, it hits 1800rpm and cuts back and drops to around 1600rpm then reaccelerates normally. Very annoying.

 

OP, I can attest to experiencing your concern with my ‘17 MT, except primarily in 1st to 2nd gear shifts within similar RPM range and most notably after the initial first few shifts from cold start. Keeping in mind what others have mentioned about the engine’s ideal RPM operating range, it is nonetheless a rather irritating experience which reminds me of riding go karts as a kid, that were equipped with the speed limiter. I assume this operating characteristic is perhaps in the name of emissions control.

My inquiry with the service department regarding this issue was met with the standard “within normal operation” response. Similar to your experience, no check engine light displays.

 

It an issue with how the plenum valve and engine fuel/VVT mapping interact from what I understand, it stumbles when the plenum valve closes or opens, I forget which, to make the manifold runners 'longer' or 'shorter' via airpressure and airflow mechanics.

You have two first step fixes A. Get and learn how to use techstream to check and see if there is an update for the ECU, you have to check manually.

Or B: Go to a Toyota service center, ask if they can check if there are any ECU updates available, you will probably have to push for it, but they will most likely just check, and they probably won't charge you, but if there is an update available, it is ~$160. You can also try citing various TSB that reference the low rpm stutter that have the fix being 'update ECU to latest version' to get it done for free, but they will probably request to hold your truck for a day or two to test if the TSB applies becuase reporting rules for Toyota.


TLDR: just go to a Toyota dealership and check for ECU update, the latest ECU version reduces the stumbling by a bit. If you wish to go even further, OVT requires the latest ECU version to work anyways, technically, but they do tune it out the stumble even more on top of the updated ECU fix.

 

Welcome to the 3.5.

There are no fixes that I have seem, although maybe some minor improvements.

Best advice I can give is to Rev the piss out of it and move on.

 

I had OP's issue with my 2018 TRDOR and 91 helped as well. Alternatively, putting my foot into it a little more also helped to just get past that point... it only appeared under light throttle for me and only on accel.