You're truck gets better fuel economy than your GTP??

No. I was hitting 20-23mpg in the GTP.

. Myth: My owner's manual says to use premium grade gasoline, but I use 87 octane and don't hear any ping.
Fact: Many engines that have premium fuel recommendations also have knock sensors. The knock sensor knows when the engine pings and retards the spark timing until ping is gone. This all takes place at a sound level below what the human ear can detect, so the knock sensor may be saving your engine even though you don't know it. The retarded timing will reduce horsepower and fuel economy, so it is best to stay with the car manufacturer recommendation for gasoline octane.

Myth: I buy premium grade gasoline because it has more and better additives to keep my injectors and valves clean.
Fact: All gasolines sold in the US are required by law to contain an additive that will keep injectors and valves clean. Tests are required and the additive must be licensed with EPA before it can be used. Most companies use the same amount of additive in all grades of their gasoline

Myth:Detonation and Pre-ignition are the same.
Fact: Detonation can hurt your engine; Pre-ignition will destroy it.

Thanks ReGiE and Herc. I saw a lot of different information flying around.

Basically, if you have a GT or an SE, use 87. You're not saving anything by going 93 unless its retarding the knocking a lot. If you have a GTP, run 91 or above.

The car won't run against your leg and purr if you 'treat it' to some 93. And if it does, the creepy HP tuning guy set the WRONG parameters when he tuned your computer.


Premium, regular, ultra are just marketing names, not an indication of quality of the refined gas.

Even after reading ReGie and Herc's comments, you may be still tempted to buy premium due to the commercials with a muscle bound dude pointing to the pump stating "ULTRA PREMIUM...WITH ICE GUARD! RUN ULTRA PREMIUM TO ENSURE YOUR ENGINE STAYS CLEAN". Well, just imagine a corp executive with a pinky ring smiling at you at the pump saying "yea, pick premium, not regular you cheap basta*d. I need a new boat."