2006 ford taurus

2006 ford taurus, v6, 115,000 miles, the service engine light came on and engine developed a rumbling sound behind grill on the passenger side, any ideas?

Take the car to an auto parts chain store and have them read the error codes - the big box chains will do this for free. Write down the exact codes (e.g. P1234) rather than what anyone says about them and post them.

Did you happen to pop the hood to try to see what is rumbling?