Hello, I used to give my car in Acura showroom, at 82K I did B2 service in Acura that time the mileage was local 17 long drive 23 . At 89K miles I have given it in Firestone for service and they used Penzoil Platinum engine oil but not sure what else they did but after that it started giving less mileage avg 14.5 local , 20 on highways. so in the next service at 93K miles I changed the only the oil in Acura showroom and its became even worse its only 13.5 local 17.5 on highways. I am unable to understand what is wrong. my car is Acura MDX 2008, mileage 93500.. I doubt that when I gave service in Firestone. Can you suggest what needs to be done to bring my vehicle back old mileage
My car has an automatic transmission.