I took my 2012 Mazda 6 in to do emissions and inspections and my OBD reading wouldn't connect. I was told the computer is not reading. I took my car to Autozone and O'Reiley's to double check and neither of them could get it to read. Now what?

I was rear ended passenger side in the back.. Floor has a camel bump in it.. Can that be repaired?

Driver side low beam headlight is not working, all fuses are good and bulb has been changed

It is an i-Touring 4 cylinder.

distinct 1-3 second lag sometimes when I accelerate from a stop, especially when engine is cold, or when turning a corner. I suspect a fuel line filter, or fuel pump glitch.

Battery has been replaced and car not showing any significant draws.