Studdering at low rpm high load

I have a 17 DCSB TRD OR Auto, with about 2k on the odometer. I first noticed about a month ago that if im at a stop and give it some throttle (75% or more), It starts to go then at about 1200-1500 RPM it loses all power for a split second then starts going again.
What has been tried:

• The first time I took it to the dealer they performed the transmission reflash TSB, and checked transmission fluid levels
• The second time they replaced the CPS, my vin wasn't officially part of the recall but they said it was close so they tried it anyway
• The third time the dealership had a toyota tech come look at it and they data logged it and sent the logs to "toyota engineers" whatever that means
• I tried cleaning the MAF sensor and pulled the battery to reset the ECU

None of these supposed fixes helped in the least bit

Has anyone had this issue with their Tacoma? If so were you able to track down the cause? Does anyone have any ideas on things I could try?
I do not want this to turn into a gripe session about the third gen, the 3.5, or the auto tranny. I do love everything else about my truck, mostly im just frustrated that my dealerhsip won't do any investigation into what could be causing this, infact the last 2 times i had it in they told me "It takes 10k miles for the engine/tranny to learn you might just have to live with this until then", but in eastern Washington state I don't have alot of choices for dealerships.

 

The local dealer had a product engineer from Japan last week look over the vehicle and pull logs, waiting to hear back with the results. My truck only does this about 60-70% of the time, very frustrating.

 

thanks for your reply, glad to know im not the only one having this problem. I called Toyota corperate and they created a case for me. no idea what it will lead to but they were very helpful on the phone. Please let me know if you hear anything from toyota, and i will do the same.

 

I understand your pain, I too live in a remote area, 250 miles west of Denver and 250 miles east of SLC. Luckily I think I have a pretty good service advisor here in Grand Junction. Do you get the stalling all the time or only intermittently?

 

Yes I get it all the time from a stop 75% throttle or higher. Although sometimes are more prevalent than others. I also noticed recently that if I'm climbing a slight grade and the truck is at 1500rpm I can feel it running rough. My theory is that the engine is running lean in these conditions, which worries me. Running lean in a high load situation long term is not healthy. It might not cause any immediate problems but could reduce the longevity of the engine.

 

NB4 CPS

 

is NB4 the model of the updated CPS?

 

no. it's shorthand for "in before". I was basically commenting that someone will be along soon to say it's the faulty CPS that seems to plague other tacomas.

 

Readings a bitch

 

Dealer already replaced my CPS

 

i know it is different since you have an auto and i have a manual, but i can absolutely assure you that there is ZERO power/torque at 1000-1500 RPM in this motor. If I was climbing a slight grade at anything less than almost 2.7k-3k, it would be a struggle. Around 2k, it would DEFINITELY be running rough/feeling like it is lugging (2nd gear may or may not be ok depending on the grade).

I don't have a response for your complete loss of power though once it reaches 1.5-2k rpm. I know that in my truck if i shift from 1st to 2nd and end up below 2k rpm and mash the gas i get an awful womp womp womp sine wave type of power delivery that rocks the truck back and forth with minimal increase in speed until it reaches ~2.3k-2.5k RPM.

Is your transmission failing to downshift? In an auto, there might be a slight lag from when you mash the gas pedal but it should jump down at least 1 or 2 gears (depending what gear you are in). I see you say they checked transmission fluid levels, did you make sure they did this manually? There is a lazy way and there is the manual way (which takes longer).

 

My 17 does the same from a dead stop occasionally. One time it almost caused an accident when pulling into traffic. Haven't been to dealer yet. Last time I mentioned something to the service advisor (transmission shifting), he said yeah everyone thinks there is something wrong with them, but they all do that. Wouldn't that mean that there *is* something wrong with them?

 

That womp womp womp as you call it is most likley just your engine bouncing around on the engine mounts, just about every manual i have owned would do this.

No, its not a failure to downshift, this is happening from a dead stop and the tranny is in first gear.

 

Well I got a call from Toyota rep today. They said it will learn not to do this and until it does I will have to live with it. Lame AF!!!

 

Yep, kind of how it goes. They did the same to me with the differential. First one they considered defective, when the second one exhibited the exact same symptoms they then said it must be normal and to live with it, "it probably won't break."

Can't have bad reliability if it wasn't a problem in the first place

 

Were you turning into traffic from a dead stop and leaning heavy into the throttle? Or was it straightlined? Just wondering if you had a little tire spin.

 

I would hope he would realize that with the trac control light flashing on the dash. Even if I start turning into a corner from a stop in 1st gear too quickly, trac control puts a stop to that real fast.

 

I'm into long shots today.

 

No, it was not traction control. It does it going straight, turning ect on, s1, 4x4 high, I have tried all permutations. The question is, if its not broke, why did they try 3 times to fix it?