My 2006 Town & Country with 15,000 miles on it was originally a CA car but I live in AZ. CA has much more stringent pollution controls than AZ. This car seems to have much less power and poorer gas mileage than the 1997 Town & Country which I just sold with 140,000 miles on it. Are there any obvious changes I can make to increase the power and gas mileage?

That could be a problem.

Unless you knew EVERY detail & how to change it to be a 49 state emission legal car, it could be a nightmare. With no doubt the ignition computer ROM is different California vs. 49 state. The camshaft may be different. The EGR may be different.

Just disconnecting everything on the emissions systems is not a good idea, either. Like, disconnecting the EGR can cause pinging & other drivability problems.

Also, I don't know if you have a pollution IM program in your area. Changing things around could cause problems with passing that.

:2cents:Get a good basic tune up first. And see if there's an ECM updates for the current configuration.