Toyota Camry Hybrid Engine Poor Mileage

For 10 Years I Have Gotten 37 Mpg. Had The Spark Plugs Replaced At 142,000 Miles. I Think He Used Denso Plugs. My Mpg Dropped To 32...

My Hybrid Car Mileage Per Gal One Is 33.8 In City And Highway At Average I Don't Know Why While In Booklet It Is Average 39 Mpg ,i Am...