[Bob'sTacoms]

Friends, a stalling problem has been discussed before, but the suspected problem/part(s) hasn't been clear to me, nor has it matched my exact experience.

• 2001 Tacoma V6, auto, 4x4 double cab at 150k miles.
• Second owner. Purchased at 75K miles. Nicely kept and well maintained per Toyota’s schedule (inc new fuel filter and mass air sensor last year). I turn my own wrench when possible.

Problem: Twice in the last year, the truck has stalled when going from highway speed (after throttle full to the floor for passing), to a full stop on an offramp a mile or so later. When it dies, there is no subsequent OBD2 / check engine light. It will restart after a couple of cranks, but it dies as soon as I put it in drive. I start it again, and it does the same thing. The third time I start it, I hold one foot on the brake, put it in gear and start feathering the throttle about 1/2 open. Once I do that, and get going again, it drives and restarts perfectly fine as if nothing ever happened.

I have tried to get it to happen again under the same circumstances, but have been uncessful.

A few clues:

• Today I filled the gas tank a few miles before this happened (I can’t recall the time it stalled before if I had also filled it up). Note: until last year, I didn’t know it’s a bad idea to continue to fill after the pump kicks off the first time.
• Both times this stall has happened, I had just driven it hard at highway speeds to pass, ie, for a moment at full WFO throttle with transmission kick down to high RPM, then it shifts up.

Fuel pump? Charcoal canaster? Other?

I’d like to catch this before it gets any worse. (Had just come back from off-roading in the desert.) Thank you in advance for any relevant ideas or thoughts!

 

[ShowStop]

Are your idle RPMs normal? What are the RPM when in park and idle and drive and idle? I'm leaning a bit toward a possible torque converter issue, but a simple vacuum leak is also possible.

 

[Bob'sTacoms]

Are your idle RPMs normal? What are the RPM when in park and idle and drive and idle? I'm leaning a bit toward a possible torque converter issue, but a simple vacuum leak is also possible.

Thanks for that ShowStop. Revs are as they should be under all conditions. There is nothing unusual in the running of the truck except this issue.

Interesting about the torque converter. Doing research, I asked this question and got the following answer.

Q: What happens if the torque converter clutch does not release?
A: Stalling. If the torque converter clutch fails to release, the vehicle may stall when coming to a stop. The problem will feel much like a manual transmission vehicle stopping with the clutch engaged (pedal released).

That is exactly how I describe the symptom. I don't understand automatic transmissions enough to know why this might be related to the two times the truck stalled at a stop sign a few miles after passing, ie, 1) going WFO throttle, 2) trans kickdown, 3) upshift at high RPM, 4) then back to cruising until fully stopped at the end of the offramp. Other than those two times, the transmission seems to operate perfectly, and I can't seem to be able to recreate the symptom.

Can anyone elaborate a little? In the meantime, I am searching. Thanks so much!

 

[ShowStop]

The torque converter "locks up" when power is in balance. If it doesn't unlock when you slow down, the transmission still tries to stay in gear from the engine force being applied, but the brakes win and when you stop the force stalls out the engine. When was the last time you did a transmission service? If its been more then 30k miles, check the fluid condition and advise drain and refill as needed. Change the filter if its been more than 60k. If that doesn't change anything, consider replacing the torque converter which will require a full transmission removal.

 

[Bob'sTacoms]

"When was the last time you did a transmission service?"

Hi. Thanks for the info. Per Toyota manual* I do: Auto trans oil change every 15K mi. Next time I'll check to see if the filter is changed (assuming it is).

*Also rear diff oil change every 30K mi, transfer case and front diff oil change every 60K mi.