Which gasoline octane should you use in the 3.8 Liter Engine...

87 is fine. i would look at secondary ignition. also, when was the last time you had the injectors cleaned?? Roy

You need to check your owners manual for their recommendation. If the car is made to run on regular, then putting premium in won't help. You will just waste full since it won't burn completely. However if it take premium, then you should use it. The question is do you have a miss or engine pinging. If it sounds like marbles banging together under a load, then switch to a higher octane and try a different brand. If there is a hesitation going up a hill, I would recommend having the car checked out by a mechanic. Write down what is wrong and when it does it. Be as detail as possible. This will help him determine the problem faster and save you money.

regular 87 octane is fine, but check for a cracked vaccum line under the '3800' shroud.