i dont see anything that says unleaded only, but i always use regualr unleaded gas. if i put the premium or super gas in would it run better or not, could it do any harm?

and is shell the best place to get gas?

There are a lot of mixed opinions about whether premium actually makes any difference at all on engines that do not require premium.

Personally, I would use regular unleaded most of the time for your Grand Prix. I am pretty sure that car does not recommend premium, so you should not have any 'knocking' problems, even when using 87 octane full-time. Check your owners manual if you are not sure.

Personally, every 12,000 miles, I fill up 5 tanks in a row of BP/Amoco Ultimate (93 octane). This fuel has a lot of detergents that will clean your fuel injectors and your fuel system. Works for me, and so far, I have not had to spend any money on expensive fuel injector cleaners.

these questions have plagued mankind for centuries. I personally do not notice a difference as long as you also do regular maintenance. Higher priced gas is thought to burn cleaner, therefore leaving the inside of your engine cleaner, therefore have to do less maintenance. I do not believe this is cost effective. Either way, the money is spent. If you care enough to put higher priced gas in your car you can afford the maintenance. In my opinion use the cheap stuff and take care of your car.

If is recommended on the owners manual yes. Using premium gasoline on a vehicle that runs on regular reprograms your emission system and might cause your vehicle to knock when you return to use regular. It usually takes a couple of fill ups to do it but can also be the result of filling up once. If you don't want to spend the extra money if you don't have to keep it regular. Besides the only benefit would be an extra few km or miles per fill up, however is it worth the extra for those km. Also using premium will increase the pressure of your fuel lines, so is your vehicle capable of sustaining the pressure or will it cause gasoline to leak out before it gets to the injectors. Well some things you can think about and to make sure you understand the differences visit www.howstuffworks.com

I have heard that BP is better.

Premium causes fewer knocks and smoother acceleration in high-performance engines.

I have heard that BP is better.

Premium causes fewer knocks and smoother acceleration in high-performance engines.