Hey everyone, I used to have an account here but it's been a very long time since I used it and can't remember any of my login info so I've had to make this new account.

Anyways, about a month ago, I wouldn't be able to get any good acceleration. It would accelerate *okay* but stumble slightly, go hard, stumble, normalize, stumble, etc. I checked the codes and it said it was a TPS issue. I went to replace the TPS and then the car would not idle smoothly or sometimes start at all. It went into limp mode.

I limped it to a shop, they couldn't figure out what it was and I needed to move so I took the car away from them early. They said it could possibly be the ECU. I replaced the ECU and then the car wouldn't even start. I replaced the IAC, APS, MAF, spark plugs, VVTI oil solenoid, and probably more. Still, nothing fixed my car.

When I start the car now, with the old ECU and all new parts, it idles at about 1200 rpm but instead goes up to 1800 rpm once it has warmed up. Before, it has also revved up and down from 1300-2800 instead of idling.

I went over the car again and realized the TPS I bought spun and shaved the plastic stops off the inside. I've ordered a new one but wanted to get any other ideas from you all. Thank you for any help.

 

Was the TPS calibrated? I heard after replacing the TPS sensor it has to be programmed in a way. Not sure if you had to remove it to install the TPS but check the throttle cable also. If it’s over tightened the idle will be too high.

 

I've tried adjusting it and resetting it by trying the method of slowly pressing the accelerator three times then shutting off the car for a while. I will try loosening the throttle cable, although I don't think it's tight. But I'm used to older style ones where there's always tension on them and I have my Lexus one close to maxed out.

 

It is also not possible to simply replace the ECU due to immobilizer codes.
The original ECU has your key codes and will start correctly.
Any replacement ECU will need to be reprogrammed with Toyota Techstream tool to recognize the new keys.

Also Techstream tool will be very useful to calibrate replacement TPS.

 

Weird, all of the videos and things I've seen never mentioned reprogramming the ECUs.

A bit of an update: I got the TPS replacement and the car now revs to 2000rpm on startup and goes up to 2600 once warmed up. The throttle cable is actually quite loose, even maxed out. It's still in limp mode and I've received a new code, P1128, which is "Throttle Control Motor Lock." I'll research some more.

 

I took out the new Throttle Control Motor, put the old one back in, and the TCM lock code went away. But now it's back to revving on it's own. Oddly, replacing the TCM caused it to come out of limp mode.

I checked the OBD2 sensor and I now have 3 codes, the TPS P1128, Vehicle Speed Sensor P0500, and the TCM lock came back.

 

I found out it's not the ECU after finally replacing it and having it flashed today.

 

Have you checked out the 'main engine relay'? Sometimes, this relay will put the car into limp mode or very not starting completely.

 

Have you checked out the 'main engine relay'? Sometimes, this relay will put the car into limp mode or not starting completely.

 

The Main Engine relay may need replacement. Check it out because it could prevent the car from starting completely. It happened to my 1999 GS300 two years ago until somebody told me to replace it.

 

I gave in a few days ago and gave it to a shop. They're saying the IAC motor is bad and I replaced that so I guess I must have gotten a dud. If replacing it doesn't fix it, he won't charge me anything so hopefully it goes through.