Is it worth buying a new car at $3 a gallon?

Because of the gas prices over $3 a gallon, is it worth selling your car and buying a new more gas efficient car?

I am going to use an average car, my 93 Lexus ES300 (same as a Toyota Camry V6) It has a 3 liter engine and gets 18-23mpg it seems like the average car in America.  I will use 18-23mpg  it has a <>15 gallon gas tank.  I can only use 91 octane or better, which would make it “Premium” currently at $3.17 a gallon next to my apartment. (Glenview IL 60025) Now it would cost me $47.55 to fill up my car, just months ago, it cost $27 at $1.80 a gallon, this is $20 more per fill up.  I drive in the city 50-60miles per day (18,200 – 21,840 miles per year). Somehow my full tank lasts me 4-5 days. This means that I have to fill up about 6 times a month at $47 = $282 per month, $3384 per year for gas.

If you go out and spend $19,000 for a 2006 VW Golf TDI (Turbo Diesel) (if you get a really good deal on it.) that gets on average 36mpg, (that’s 2x better then my Lexus) it would cost you $1692 and a saving of $1692 per year. My car is worth $4000 to sell on the street, I can use this as a down payment, that leaves me with a balance of $15,000 (ball park figure) It would cost me almost 9 years for it to start being a good and wise decision. This means after 9 years, you will be saving $1692 per year until you sell it. After 9 years, you may get about $2000 for selling it.

So if I am right, it may not be worth switching to a new car just yet. Maybe until gas prices go up to $6-$7-$8.. ?? a gallon. But if you are ready to buy a new car, think about Diesel fuel cars such as VW TDI, Mercedes CDI, Dodge Sprinter and Jeep Liberty Turbo Diesel.