which fuel type is better for pontiac sunfire 2004??

I've had good luck runnin' the 2006 MINI with Chevron with techron, 91 octane or perhaps 93, but mileage really is the key, why for if you're stuck in the same traffic?

The type of gas isnt turning on the light. You should get the light checked and see what dtc(s) you have. As judge said try different octanes to see what gives you the best fuel mileage. But it will run just fine on 87 octane. Ive never noticed a difference in the different companies it all comes the same place they just put different chemicals in them and say theirs is the best.

Regular grade fuel is all your Sunbird will need. Higher Octane ratings have no effect on the engines in these engines. All brands are virtually the same so shop on price and not brand. There is no "best brand". As was said in the other replies, get the problem code detected and fix the cause of the check engine light before it gets to be a bigger problem.

tnx for your attention,but just for check engine they want 80 to 100 box for just find out the problem,!!:(( and i think the problem comes frome catalik convertor or somthing like that because every thing do well just when the light comes on maybe in the hills i have problem and the car cant go as well as allways and no powerfull..??

I see this is several months old, so I assume you've figured it out by now. But, I figured I'd comment anyway in case someone else is having this problem currently. For starters, you can have any "Check Engine" light read at auto parts stores like Advance Auto Parts, Auto Zone or O'Reilly's. They will read the codes for free. It's more generalized that what the shops charge you for, but in most cases and with a knowledgeable sales person, you can get a pretty accurate diagnosis with out paying the outrageous shop fees. Secondly, if your Check Engine light is coming on after you put gas in it, chances are when you have the codes read, it'll come back as an "Evap" code. This usually means you have a bad gas cap, not because your car doesn't like the grade or brand of gas. Although the cheaper gases do tend to have more water content, that usually would not cause your engine light to pop with out showing other signs something is wrong. I'd replace the gas cap and go from there - because they do wear out especially if you fill up a lot. You can get after market caps at any auto parts store, Walmart, and even some farm supply stores where they might be cheaper.