Xterra Owners Club.
This is your wife's car right?
"'Nuff said"

In response to the "does turning the O/D off actually increase acceleration" question:

The answer is yes, and not just for an Xterra, but pretty much any vehicle with an automatic tranny and overdrive. Same thing as driving in "D", as compared to "O/D". By driving with the O/D off the transmission allows the engine to rev higher before shifting gears up. OD is great for the highway when you're at a fairly constant speed as it keeps the RPM's lower and thus conserves fuel usage.

Disclaimer: I'm fairly new here so feel free to correct any of the above incorrect information.