Premium Fuel In A Gtp

[MIKE66G]

I Have A 1997 Grand Prix Gtp Which Calls For Premium Fuel. The Last Couple Of Years I Have Been Running 87 Octane In It And Have Seen No Difference In It.the Car Runs As Fast And Well As It Ever Has And The Gas Mileage Is As Good Or Better. Why Do They Call For Premium Fuel And Do You Really Need It?

[BNaylor]

Whether you can get away with running regular or mid-grade versus premium in a L67 is a matter of how you drive. The premium was required due to the supercharger and PCM programming.

You will really not know what type of damage may be caused by running regular until you check knock retard (KR) with an appropriate testing medium or device.

[GTP Dad]

The manufacturer specifies 93 octane for a reason. I know it is more expensive than 87 but it costs a lot less than major engine repairs.

[momosp02]

hey ...i have a 99 grand prix gtp with about 60 thousand miles on it. every so often when i start it for the first time in the morning (only the first start of the day) it will start fine then die right away. it will do this repeatidly untill i rev the gas for about 30 secs. i went to a gmc dealer and asked the mechs. if they ever heard anything like this before, they said it may be that the engine was having trouble with the 93 octane in the morning and suggested that i run a few tanks of 87. ever heard anything like this before???? also my O2 sensors are busted but have been for like 4 months .. i am replacing them this weekend so maybe that will help? please help ...

[BNaylor]

^^^^^I've never heard of that suggestion before.

Check out the fuel pressure. You may have a bad fuel pump resistor or fuel pressure regulator for a possible fuel problem or a crank position sensor for spark.

BTW - It would be a good idea to get the 02 sensors replaced.