Issue... No throttle response while climbing

I've run into an issue with my Tacoma(AT) where intermittently climbing up hill it suffers extreme power loss and putting my foot to the floor has little to no effect. RPMs remain low and it's like the truck isn't even trying. In all cases I'm rolling pretty slow, under 5-10 mph, and should be in 1st gear naturally.

The first time I experienced this was last fall at altitude(8,000ft) with a small SXS(honda Pioneer 500) in tow on a light trailer. I would slow down for a turn on a flat gravel road, then try to accelerate with no throttle response. I wrote it off to altitude and the trailer(though total weight was less than 2000 lbs).

Then, this past Friday, I was taking my nephew fishing and about 20 feet from cresting a 100ft. 40%+ grade dirt trail, I got that old familiar feeling. What made this scary was the thought of the truck stalling out and the consequences of rolling/ sliding backwards with no power anything. Fortunately it limped its way over the top of the hill at a disturbingly slow pace.

Question is, has anyone experienced this and are there any remedies outside of replacing the truck?

 

This does not seem remotely normal even when "normal" is throttle delay from the pseudo atkinson. Go get it checked out by the dealer and use that warranty.

 

I had an issue with my throttle not responding after sitting and idling for an extended period of time in extreme heat. I read and cleared the codes it was giving me, misfire cylinder 1, and 2 oxygen sensors. It ran fine after that and letting it sit for a bit.

 

Check your mass airflow meter, next, fuel pressure during the situation. If those trucks are equipped with MAP sensors apart from the MAF, make sure that thing is working correctly also and is capable of voltage detecting and holding vacuum. Short of that, if you are still in warranty, it would be wise to bring it in.

 

Bad fuel pump

Have you done the CMP sensor recall yet?

 

traction control is my vote

 

This ^ Traction control will limit the throttle so you are less likely to break traction!

 

We have to assume he is intelligent enough to turn off traction control if he is intelligent enough to post a properly written comprehendible message for us to read. Lol.

 

+1 for the trac system. Spoilers: It is still partially on even if you turn it "off".

I've yet to verify that this issue exists with traction control fully off (as in hold down the trac button for 5 seconds or what have you), but this happens in AUTO LSD mode as well.

If you had a mechanical issue you would feel it "trying" to go faster. It's not trying.

I experience the same effect with my 4 cylinder climbing hills at altitude when off road. You had the truck in "D" and not any of the "S" modes, correct?

It's dumb as hell but what is happening is it's computer is smart enough to know banging out a downshift will cause the wheels to spin, but it shifted into too high of a gear to begin with so it just sort of gives up and tries to inch you over a grade in like, 3rd or something.


It won't stall on you, it's just overbearing electronic nannies combined with an EPA-whipped shift logic that is like "ok we're going 20 MPH, time for overdrive!"

 

For some reason all this makes me think of this: (too much computer)
https://youtu.be/Q8qAkUA8ZF0

 

Man, I don't know if the traction control would limit him as severely as he describes unless it's fucked... the truck basically fell on it's face. Mine's a M/T, but even with the nanny systems fully on, the truck will break loose a bit and accelerate while the traction indicator flashes at you. With the nanny shit off (press and hold the button until Auto LSD goes out and the other indicator appears), I can make my truck drift around corners - no flashing nanny idiot light. It is truly off.

There have been other members who reported actual stalling while going up/down at steep angles, but some have also reported the dastardly transmission overtemp warning at the same time - this has been an indicator of a bad CPS in some cases.

Of course, my experiences have not been at high altitude, so there's that.

 

Yep.

 

I've drifted through muddy roads firing some pretty gnarly rooster tails of muck as well... with trac ON!

The traction control is truly fickle but I have no doubt in my mind it would reject a downshift and/or pull the throttle by wire actuation to near-zero if it gets "caught off guard" by suddenly needing to climb in a high gear that it can't climb in, but on the edge of traction so a downshift would definitely spin the wheels.

My 4 banger is a good control because it does not have the same CPS issues as the V6, and I have indeed experienced the same phenomenon the OP described, which would point to the trac system, as it's about one of the only common threads.

I think it's still worth it for OP to look at the CPS, but like I said, with misfires and stuff you "feel it" ... it tries to go but can't, you get slow acceleration with a "puh-puh-puh" sputtering, or a vibration, or something. This sensation is of the truck outright refusing to downshift or give you extra throttle.

 

Yeah the downshifting with the auto in this situation is something I know nothing about, but I can tell you if I'm in 2nd at the wrong time the truck is snail like until the revs come up.

 

If he left it in D while towing and didn't do anything else, TC probably kicked in to limit throttle response. If he kicked it over to S3 or S4 with ECT engaged and TC off he might have had a bit better result.

Hard to diagnose from the initial post as a lot of variables are in play.

40% grade on loose dirt is pretty steep.

 

Thanks for all the input. The truck was in D, not S(both occasions), and traction control button off for the recent hill climb. I've noticed on the display an intermittent "traction control off" signal, while the "auto LSD" light remains on as a result of turning off the trac control.

What doesn't make sense to me is there was no sensation of wheels slipping or the traction control engaging or any dash light indication in either instance with trac-c on or off. I'll see what the dealer has to say about it. I'll also lose it if they tell me the transmission is still "learning" how I drive.

Thanks again, all.

 

You were in Auto LSD mode, where traction control is not fully off if you got over a certain speed. If I remember right that "certain speed" is very low, like 9 MPH. That's why you saw the TRAC OFF icon disappearing, it was coming back on.

ON > Press button and release > Auto LSD mode
ON > Press button and hold for ~5 seconds until a different light comes on > VSC OFF Mode

It's a shame we need a fracking flow chart to explain this but here:


Notice the all the * at the bottom. Basically the truck turns them off if you are at a standstill, but they come back on when you pick up speed. Or, in the case of VSC off mode, it comes back in when it thinks you've really gotten yourself into a massive screw-up.

They are going to tell you it is normal. The traction control blinking light only occurs when there is real slippage detected, the nannies kick in beforehand and traction control isn't just applying the brakes- it cuts the throttle too.

 

Thanks for the insight; this is helpful. I've never gone in "VSC off mode", wish I knew about it in the winter for parking lot donuts. Serves me right for not studying the manual... I'm going to need to test it out and see if I can actually spin a tire, didn't think it was possible before.

 

The manual does a fairly terrible job of explaining things. One of the best descriptions I've found of how everything works on these trucks is through this thread.
https://www.tacomaworld.com/threads...easy-to-understand-i-hope.70551/#post-1333613

 

I just have one question..where is the fuse for this crap?! JK