Theres a really loud rattling sound coming from under my truck after i went down a gravel road. The check engine light came on so i took it to autozone. They got P0441 and P0073 witch they say are evaporative emission system small leak/no flow condition and ambient air temerature sensor circuit high.

 

Anyone know what could be causing the loud rattling sound?

 

So the loud rattle started after the gravel road? it's possible that a rock or two got stuck inside one of the many voids in the frame rails. One of my sockets has meet the same fate