I just totaled my 99 so need to upgrade. I am really into fuel economy. I may get into a 3rd Gen vehicle maybe an 2003 to 2005. My truck had a 3.5 rear end and auto and I was allways looking to bring the RPM down to improve fuel economy. It looks like the 3rd Gen has as the tallest rear end a 3.7 which would be worse than mine. (Maybe I'd need to suck it up and get a Gear Vendors overdrive unit) Are the 3rd Gen Automatic and Manuel Transmission ratios in Overdrive gear about the same as in the 99's (The auto was .69, and the 5 and 6 speed were .73 and .75) Also, are there specific engines in the 2003 to 2005 I should look for that do better fuel economy wise?

 

The 3.73's on a 3rd gen will be similar to your 3.55's in RPM per MPH because they have 17" wheels. The 03 and 04 models get a little bit better MPG because they have fewer injection events than 04.5 and up models.

Nick