This past weekend, I detailed my engine bay, it needed it pretty badly as this truck has never had it done. Being a car detailer in the past, i just do what I've done hundreds of times. Used a non-abrasive degreaser and scrubbed the whole engine bay rinsed softly with water, treated and dressed the rubbers and plastics. Turned the engine on and left the hood open to dry, again just like usual.

I went to drive the car the next day, it started fine, and drove fine until about a half mile from my house, I was pulling away from a stop sign, and right about halfway through second gear, the car kind of "hiccuped" and a check engine light came on. From that point on it would drive perfectly fine, but it would hold gears out way too long before the A/T would shift itself.

Usually the A/T shifts around 2500 for me and my style of driving. Well of course it was holding it out to about 3500 and sometimes higher in the lower gears. I went straight to a shop here that will do free check engine lights, I've used these guys before and they give very accurate reports and dont try to Bullsh*t you.

The code came back as a "P0120" [Indicates a fault in the Throttle/Pedal Position Sensor "A" Electrical circuit for a predetermined period of time.]
Code also reads as [TP Sensor or Switch "A" Circuit Malfunction]

I had a feeling it was electrical, since I did just put water on everything -.-
So I went to the TPsensor and cleaned the wires and what I could see without taking it out with Electrical contact cleaner, restarted the car, and the code is gone now and the drivability issue has improved but not completely gone, again it drives fine in all other ways, I just put a ton of work into the engine, and once Im cruising of course you would have no idea anything is wrong. I can just tell after driving this truck for a year, the shifting times are off still ...even with no code.

Does this sound like just an ECU reset would fix it maybe? Or do you think now that the code is gone its trying to relearn my driving style? This is out of my range of knowledge so Im seeing if anyone else has a theory or thought. Thanks!

Sounds like moisture in the TPS to me. You probably just need to replace it.

I took the entire sensor off and cleaned the insides with cleaner, letting it sit now and will test drive later.

$35 for a new OEM sensor off Amazon. Just buy it, clear the code and drive.

http://www.amazon.com/Genuine-Toyota...osition+sensor