Electric fan is a great idea. I _HIGHLY_ recommend using a
Delta Current Control controller for this:
http://www.dccontrol.com/constant_temperature_controllers.htmThe motor has only 130,000 miles and it's tired? Who owned the truck before you, Enterprise Rent-A-Car??
Seeing how it's an automatic, I'll leave it at this: It's always gonna feel sluggish until you change to a more powerful engine. You may not like this, but I'd recommend one of the following: 1) Sell and replace it with a 5-speed version, or 2) Do an engine conversion to a 3.4-liter 5VZ-FE. Short of these two options, if you are already dissatisfied with its performance combined with its handicap (auto), I don't think you'll ever feel satisfied.
If you or any other automatic owner is thinking about doing a manual transmission conversion, I advise against this. Do it the proper way by finding a factory equipped 5-speed truck.
BigMike
