I have a 2005 Five Hundred with 42,000 miles. I'm experiencing rough idle, stalling, and poor gas mileage. Since my purchase in May 2007, city mileage has dropped from 20mpg to 18mpg. The engine light is not on. I have taken the vehicle by Auto Zone and their code reader revealed no codes. Any ideas?

 

How many miles are on the car?

Are the basics covereslike; fuel fitler, air filter, tire pressure, clean thorttle body?

Probably would hurt to run some fuel system cleaner through your next tank of gas.

 

Give it a good tune up and check the throttle positioning sensor.