Don't know what year your Jeep is, but you are going to take an absolute butt kicking when you go to trade it in. Also, the 4.0 is a six banger, so it can't be all that bad of a gas guzzler. Bigger cars/trucks aren't selling as well with higher gas prices, so you are going to get slammed with that when you go to trade it in. Now figure this.....if calculate the money that you will loose on the trade in, added to the difference between that and the price of a new car and add it all up together, that still is a lot of gas. Yes, gas has gone up, but you may find that if you change some things in your routine, you could be able to make it up. Also, don't forget to add the difference in auto insurance too. Don't assume it will be cheaper just because your getting a smaller car.