What year of automatic camrys has the best gas mileage? whats difference between 4 cylenders and 6 cylenders?

The more cylinders, the more fuel the car will waste, but in return you get more power. Japanese cars have great power even with smaller engines. I drive a mustang gt with 8 cylinders, and it guzzels gas like no tommorow, but I get amazing power from it, and I love it. The 4 cylinder camry you have posted looks good if you want to save on gas, and not pay a lot for insurance. Not all engines with low amount of cylinders are bad though, for example the Inline-4 cylinder engine SR20DET comes with a stock 250hp. It's all about the way you tune your engine to make it run how you would like.