I have 2000 dodge avenger with the 2.5L engine that started making this loud lawn-mower sound. I was driving down the freeway going 65 and hear a loud pop followed by the mower sound followed by the check engine light flashing. I kept my eye own both the oil and temp gauge and they remained put. Can any one help me diagnose this? thank you

 

Sounds like you popped a spark plug...or maybe just an exhaust leak