i have an 04 TL automatic and i was sitting at a stop light, and the rpms usually idle at about 700, but it went up to about 1200 then dropped to 100 and almost shut off. after that the engine has a loud knocking. i also noticed that it doesnt make much power since then. now its just sitting in my driveway...any ideas?

 

check the engine oil level and make sure its ok
It the computer thought something was wrong= it goes into limp mode and wont rev over 2500- makes you aware there is a problem that needs dealer attention

 

no def not oil, and its not in limp mode. im getting it towed to a mechanic that my stepdad used to work with tomorrow...