Gas Pedal Adjustments.

I bought our 2004 new and have been driving it for 5.5 years with 41,000 miles on it. I have noticed a drop in mpg and have noticed that the gas pedal has become more sentitive so getting to the "glide" and battery only mode is more hard to come to. I have noticed that I can be going down a slight hill and that the ICE is running and yet I'm at the 90 mpg mark on the MFD. Before I go to the dealer I'd like to know if there is in fact any kind of adjustments that can be made? It just seems like the gaps between the modes are much more sensitive then before, hence my drop in mpg.