Very recently, I have noticed a significant loss of gas mileage on my 1999 Altima, I used to get 26-29 MPG until 3 weeks ago. All of a sudden I am now at 17. No engine lights have come on, and the car seems to be running fine, maybe a little more sluggish. I have replaced rotor, cap, plug wires, transmission fluid, fuel filter, switched gas stations, nothing has seemed to work. I thought it could be an O2 sensor or plugged catalytic converter, but again there have been no service lights displayed. Any suggestions? Thanks in advance. jb
Spark plugs? Bad wheel bearings, stuck brake caliper, bad calculator, city driving, stolen gas, fuel injector jammed. I don’t believe you got 26 to 29 MPG. The overall MPG rating on a new Altima is 23. Consumer Reports. You should get at least 17 MPG.