My car has same code P0171 only, but nothing wrong can be told when I drive my car except check engine light on. I sent my to Toyota dealer, they said thermostat need to be replaced, but I paid $300, still light there. so Toyota will give me no more charge repair my car. then they replaced intake gaskit, still didn't help. finally they replaced one used part MAF sensor to fix my problem. they didn't want me know that, but I still figure out what they did with my car, because first time I guess that part defective and I left mark on it. so I thought this is a ture problem. later on, if somebody