I am very frustrated with my car! I just replaced the 2 front sensors (Bosch) bc it was giving me a specific code of p0171 system too lean. After it was fixed the codes cleared and running good, then the next day cel & trac came back on. Reading the same code & now when I mash the gas I hear a loud rattle coming from under the vehicle. Im in need of some advice please help.

 

Clean or replace your MAF sensor. Also, don't buy Bosch sensor, they sucks - TOYOTA part only.