Acceleration problem

Acceleration quit twice during a road trip with my 2000 Tundra V8 170k miles. Rebuilt transmission 50k mikes ago. Accelerator quit while I was on the freeway (engine did not quit). I turned off the engine for 10 minutes and it allowed me accelerate only with full throttle and no kickdown with the transmission (no downshifting to increase acceleration).
Error codes P1120 and P1121. I replaced both throttle position sensors (TH451 and TH263 from O’Reilly) and cleaned the throttle.
Minor improvement with acceleration at 1/2-3/4 throttle (or pushing gas pedal 1/2-3/4 of the way. Still no kickdown.

What else am I missing? Clogged fuel filter? Transmission solenoid problem?
I still need to clean the Mass Flow Sensor as suggested here.

 

When you changed the TPS sensor, did you check it to make sure its calibrated correctly? The PCM will want to see that the TPS sensor is displaying what it believes to be the correct throttle position based on what the MAF sensor and the MAP sensor is reading. If its off, it will go into limp mode which is what you may be experiencing.

 

Check transmission fluid?

 

You will need a volt ohm meter to check it. I'm trying to find what the voltage should be closed and open.

The P1121 code is an accelerator position sensor code.

You need to calibrate the TPS sensor and then the accelerator position sensor. Because these aren't calibrated the computer is going into limp mode because its sees the accelerator at 20% and the throttle body at 30%, for example.

Calibrate them, unhook the battery, hook it back up, key on, accelerator to the floor 3 times, start it up. If that doesn't do the trick, let us know.

The only other thing I can think of is the motor in the throttle body is going bad.

This is where a scanner that can see throttle position will help you. Unfortunately unless you have something like HPtuners or a Snap On Solus system, its going to be hard to pinpoint.

 

Thanks for the replies! I recalibrated like you mentioned above and it didn’t fix the acceleration issue. Also since I replaced the sensors it shifts harder and idles higher (around 1700 rpm). The idling I think is due to the TH263 sensor position that I can adjust a little.
I forgot to mention the previous owner said he had replaced the throttle body.

update: now the ignition won’t turn to start. There may be some anti theft mechanism. It will turn to accessory and allow me to shift but won’t turn to ‘on’ or ‘start’. The steering wheel is not locked.

 

A lot of this is pointing to an electrical issue.

When you say it won't start, do you mean it wont turn over or it turns over but doesn't fire?

 

The key literally doesn’t turn to on or start, only to accessory

 

Silly question but did you try turning the wheel left and right while you are turning the key? Seems simple and I'm sure you've done it but I gotta start with the simple fix first LOL.

 

I had to take momma bears 4runner last week, so she took the tundra, calls me freaking out because the key won’t turn; told here the same, turn the wheel back and forth while turning the key. No go, I thought wtf I just used it. I had to leave work, halfway there I realize she has to be using the spare key for the 4runner........sure enough, stuck the correct key in and fired up.

 

As I mentioned above the steering wheel is not locked. I’ve done that before and had issues with a key not turning the ignition in another vehicle.
The Tundra key worked this morning But didn’t after I did the calibration method mentioned above and the second Key I have also didn’t turn the ignition.

 

Maybe the park/brake safety switch?

 

No way that calibration messed with the ignition.

I think you have an electrical issue.

 

Maybe the tumbler in the ignition, maybe both keys just don’t work anymore at the same time.
I think there is a weird electrical issue. I’ll let you know when I find out what’s wrong.

 

Check up by the kick panel for corrosion. theres a small connector that directly affects throttle operation that corrodes. had to fix one a few weeks back

 

I got the tumbler in the ignition cylinder replaced, it’s starts now but still has the acceleration issue when the engine is warm.
I didn’t see a connector at the kick panel or near the gas pedal. I have a v8, I don’t know if you have a v6.
I replaced the “Standard Intermotor 4 Terminal Fuel Injection Throttle Control Actuator” part# TMC1 at O’Reilly, it’s next to the throttle position sensor.
That didn’t fix the issue either. I took it back to the mechanic who scanned it with a snapon scanner but it only came up with the same codes I got previously.

 

I’ll have to dig up the diagram when I get home tonight.

 

I removed the connector in the image and replaced it with S1931 so now it is connected directly instead of having the gray connector.
After doing this, upon starting, the engine revs on its own up and down between 2-3k rpm. When pressing the gas pedal it revs high to 6k rpm. I rechecked the wires and it did the same thing.

I guess we can’t upload images here.

Update: I connected the wire based on the previous color combinations but I tried switching wires 2 and 3 (idle signal and tps signal) and it fixed the weird revving and returned to the same 3/4 throttle acceleration problem.

 

I think you need 10 or 20 posts before you can upload pics. Keep posting and you’ll get there.

 

What happens if you pop the hood and actually rev it with the TB? Or turn it with the truck off to hear if the little part on the left of the TB sounds ok?

 

You mean moving the accelerator? A cable connects the gas pedal to the accelerator position sensor on the left of the throttle body. To answer your question, same issue occurs. I've replaced sensors and wiring, I don't know what else to do, so I sent it to a mechanic a friend recommended. He thinks it possibly needs a new PCM. I'd be surprised if that is the case.
Is the ECU/PCM located above the gas pedal, close to the steering column?

 

Yeah, I had em backwards. I'm all ate up with the dumbass lately.

Pic ain't great, but it's the only one I got.

 

Regis. Can I phone in an interpreter on this one?

 

I was scratching my head with that one for a while. I think it says "listen here"

 

Ahh. I kinda see it now.

 

Sorry. Yeah, that's Texan for listen. It's got a southern drawl on it.

 

Can you elaborate on the location? Photo? I have had my Accelerator Pedal Position Sensor fail 3 times. Maybe this corrosion is what is causing mine to short out. Any help would be appreciated.

 

No photo I’m afraid, my truck doesn’t have this setup.

 

OEM sensor?

 

Yes, OEM Throttle Lever Assembly. P/N: 22060-50011

 

Thank you.