Need help on my sunfire -- Code - P0122

[azsxdc2008]

Ok, here is the symptom, I'll describe it to the best of i can

2001 sunfire SE 4dr Automatic, 2.2L with ~15000km

Fisrt of all the ETS light is on, then i'm experiencing a really really poor acceleration, the RPM is nearly 3000rpm/min and i still can't get to 40km/hr..i can hear the engine running really loud but the car just won't go any faster. it stays at the gear and won't shift to next one. then when i put more pressure on the gas padel, made the RPM to 3500-4000rpm, it will eventurally shift to the next gear, however, the car gave a strong jump forward, it's like someone kicked from behind...in this situation, OBD code reader gave me nothing .

the check engine light also comes on, OBD code is P0122....

However, every symptom disappear if i just pull over, and turn off the engine, leave it for 30 seconds. Everything is good again. I can run for another 10km no problem....then the problem happen again.

Any comments are appreciate.