I went to the dealership for a battery change. After the battery change the mileage of my car went down by half. Before the battery change my mileage was around 30 to 35 MPG and after it was 15 to 20 MPG. I haven't changed anything about the car (same routs, same gas, same driving habits).
When I called the dealership to ask what may have caused this the answer was that there were too many variables and that I need to make a log, where I log where I go, how much I drive and which gas stations I use.
However, I have no changed anything about my habits since i bought my car 5 years ago. For 5 years my mileage was relatively stable between 30 to 35 MPG and now it changed. What would be the benefit of making this analysis. Analysis is only beneficial, if you have a baseline and I don't have a baseline, because I will be logging this information on an on-going basis.
I pointed this to the service agent and the response was that there were too many variables...
Needless to say, I would not recommend this service center. You never know what may happen to your car.