What type of fuel should i put in a 2005 grand prix? should i use regular, mid or premium? which one is best for the car?

Using the recommended 91 octane gasoline is your best choice. Using lower octane can cause fouling, miss-fire and detonation(pinging). While not too detrimental in the short term, this can cause premature engine wear over time. If you really need to save money at the pump, Try mixing regular or mid grade with premium in various ratios until you find a blend that runs well. Or Don\'t buy a car that requires premium.

Hello restrada.

Your Pontiac original specification calls for Dexcool coolant.
This is an orange colored fluid.
If the green regular type has been added the system should be flushed and refilled with Dexcool.

Thank you for using FixYa.

KL

not usually, unless you bought a special model.....what does the owners manual say.

This is a wide range of fuel types. Minimum Octane level to run decent is normally 87. Up in the northern areas and hilly states I've seen this a little lower. Typically your choices are 87 octane, 89 octane and 93 octane. I recommend using the 89 octane or mid grade to get the best mileage and consistent performance from the vehicle. You will get better mileage from the higher 93 octane or Premium but this is off set by the increased soot and build up over time and the mileage isn't that much better to justify the cost between the Mid and Premium grade fuels.

20w50 gtx or castrol

87 octane unless you have a racer

Sounds like it is misfiring.
Try changing the spark plugs and you MUST run premium fuel.

when you open the gas flap to put gas in it should say "unleaded fuel only" or " premium unleaded fuel only". If it says premium only use premium. If it just says unleaded then you can use normal unleaded gas. But some stations have a lower grade unleaded gas. Use 88 octane or better.

HI. i recommend using the premium in this vehicle. This will ensure optimal performance. The fuel system will accept the regular blend as well but, this is not what this vehicle was engineered for. the regular blends octane level is not sufficient for optimal acceleration and overall performance.

Please rate and god bless:)

u cud use the premium gas....ur manual says so...or a higher octane gas is also recommended