2006 Hyundai Sonata • 4 cylinder FWD Automatic • 94 miles

Hi I have 2006 hyundai sonata and it has 94K miles on it I have already changed my spark plugs and cabin filter and air filter. Sometime I feel hesitation while driving at a speed of 45 or 55 miles/hr if I keep my speed constant. I asked the auto zone wht to do should I change my fuel filter or wht shoul I do, he said to me 06 sonata doesnt have fuel filter outside u have to replace whole fuel pump. One thing I have noticed is that my engine light was on couple of times and then it went off automatically and when I checked it out it shows me oxygen censor.
can u plz help me out with this problem, I guess bcz of this problem I m not getting better fuel mileage and I drive most of time on highway I usually get 28 or 29 and the car says it should get 35. Its a 2.4L engine
January 22, 2011.

I would start with replacement of the oxygen sensor

Dr. Hagerty
Jan 22, 2011.