OK, here's what happened:
Last Saturday I pushed my -91 out from the garage - pushed did not start - to make room to work on my Harley. After few hours I was done and I started the engine and drove said 15 feet back in. Engine was running slightly faster idle when I shut the engine off.
Today I went in the garage to take LS out. I started it and it did not start as it usually starts with ease but...well...differently. I noticed immediately that the idle was very, very rough and there seemed, well, that's what it felt, to be all sorts of mechanical noises. I shut the engine off almost instantly.
After a while I started it again and it was slightly better but not what it should be. I listened to the engine idling and reversed the car out and shut it off.
Something in the back of my head told me to reset the computer and I pulled battery cable off and let it sit for a while. I then put the cable back on and started the car. Most of the roughness and such were away and I went for a ride. Now after 20 miles or so computer seems to have re-learned and 1UZ-FE purrs again smoothly. With a tick-tick but smooth nevertheless.
What exactly happened on Saturday when I shut the engine off in fast idle? Was it in some sort of warm-up phase that messed up the computer?
If I had not reset the computer today would it have learned and cleared the situation by itself?