Torque converter randomly locking/unlocking

[BirdusZippidus]

My '99 4Runner SR5 4WD has been acting up. My wife reported the transmission shifting a bit weird, and it dying on her once at a stop sign.
I test drove it and it seems the converter is randomly locking and unlocking. Didn't stall on me though.
I did a top end cleaning with Seafoam, followed up by a cleaning of the MAF just to try to make sure there were no issues there. Not kicking a CEL, and no stored codes.
Right after I got it a couple months ago, I got a CEL for the TPS. Replaced the TPS at that time, and the code never came back.
I also replace the original radiator as a preventive measure. No pink milkshake.
Obviously hoping it's not a TC issue or worse, but I'm not sure where to look next.

 

[19963.4lsr5]

It still acts like a bad tps.

Did you use aftermarket or OEM?

Does it do it holding a steady throttle?

Is your TV cable “aKa kick down” sticking and adjusted correctly?

Do you have a scanner that reads live data?


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[BirdusZippidus]

It still acts like a bad tps.
Did you use aftermarket or OEM?
Does it do it holding a steady throttle?
Is your TV cable “aKa kick down” sticking and adjusted correctly?
Do you have a scanner that reads live data?

Aftermarket TPS. VEMO. That was two months ago though. And man... that was a PITA to replace even with the hood off.

Steady throttle seems to be okay, but it will randomly lock and unlock under acceleration.

I gave all the cables a visual inspection. There is some slack in them at idle, but I expect that.

What live data? I've got a both a bluetooth OBD2 dongle, and a Subaru/VAG cable. I don't have any Toyota specific software or app though. I've got the Torque Plus app that I generally use for pulling codes.

 

[BirdusZippidus]

Well.... I just went out to plug in my scanner, started it, and it's hunting for idle speed, running rough.

No CEL, but did a scan and it shows P0121 pending fault.... throttle position sensor.

DAMN.... I mean, I'm glad it's not the transmission or TC, but that thing is a PITA to replace.

Edit....just went looking for an oem sensor. Discontinued. Guess I need to go raid the local parts truck.

 

[Bad Luck]

Well.... I just went out to plug in my scanner, started it, and it's hunting for idle speed, running rough.

No CEL, but did a scan and it shows P0121 pending fault.... throttle position sensor.

DAMN.... I mean, I'm glad it's not the transmission or TC, but that thing is a PITA to replace.

Edit....just went looking for an oem sensor. Discontinued. Guess I need to go raid the local parts truck.

Might check with these guys first: Toyota OEM Throttle Position Sensor - 89452-35020

 

[19963.4lsr5]

Pull the throttle body to replace it.

That app should read live data and show you the tps position.


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[BirdusZippidus]

I didn't have the luxury of waiting until next week for OEM. With my wife's other car having an intermittent crank/no-start issue, I had to get one sorted, and the 4Runner seemed easier.
Checked with the local Toyota dealer. No luck. So I bit the bullet and got another aftermarket from Advance Auto Parts.
Had to bust the old one off to get on the seized cammed out screws with vice grips.
Got a couple of button head allen screws to replace the JIS Phillips. Top hole was galled though, so it's currently held together with a zip tie and one screw until I can re-tap that hole.
What a pita.
Anyway...test drove it and all seems fine. No code. No random lock-up. Done for now.

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