I got my new injecotrs put in about 2 weeks ago. My fuel milage is still at around 12 MPG instead of the 15-18 i was getting before my injectors started messing up. Air filter is clean, oil is fresh, and still no gain? What else could it be or should i take i back to dealer to find out what is going on. I just ran out of 36k bumper to bumper warrenty. Thank guys