My handbook says i should use premium gas but do i really have to? I have a 98 GP GTP

The higher octane will prevent detonation.

When you fill up..the difference in premium and regular is what like 20 cents? So 20 cents times about 15 gallons is exactly 3 dollars. Not that much at all. Everyone thinks that its like twice as much but it really isn't. Do yourself a favor and put up the extra 3 bucks for premium...

I always put in the best gas I can, not only does it burn slower and give you better milage but its cleaner

Premium all the way, that what I've run on all my cars since I started driving. It's worth the extra money... just do it...

Although, recently where I live they raised the prices for plus and Premium, is this nationwide or what? It's now $.15 more for plus and $.30 more per gallon for premium.

So if i put Premium in my GT is there any harm in doing so, and what are the benefits? better gas mileage? does it harm it if gas mixes, if i put in like a half a tank of premium and it gets low and i put in regular? will the mixing harm it or just blend to create the midgrade?

Blend as you wish, no harm

The only harm you could do is to put inferior gas in or the lowest octane ytou can get.

\The higher the better in my opinion


One myth is that the higher the octane the more horsepower you get, that is untrue

1. Using a higher octane gas than recommended can leave deposits in your engine because it cannot burn the fuel completely.
2. Mixing regular and premium will net midgrade. A normal gas station has 3 tanks: two regular and one premium. The midgrade is blended.

Just put in premium all the time, like Kev-GTP said, its only $3 more, which does add up but no big deal...

"1. Using a higher octane gas than recommended can leave deposits in your engine because it cannot burn the fuel completely."

so what about in a GT, i use premium every time i fill up, should i be filling with regular? or maybe just plus?

I use premium evertime with my GT. I've never heard anyone say that it was bad for a car

I've never heard that premium was bad until this series of posts. But I think premium in a GT or SE is overkill and probably a waste of money. Premium is really meant for forced induction cars or highly tuned NA cars.

I don't know how it is anywhere else, but Premium is actually $.30 more a gallon. Times that by 15 and you get $4.50. Still not a big deal really. I put low grade in because I have a GT and I really don't feel that i need it. My car runs just fine with the low grade. I used premium for a month before and didn't see a difference.

Buggy, how was the visit to Blue Springs... oh yeah and I mentioned that it was $.30 higher a gallon... I wonder if that's just around KC or what?

Maybe you guys are right...I always thought that like regular would be like 2.80, then it would be 10 cents more expensive per grade that you go up. Maybe I'm just an idiot...

i just use gas for mine, its a older car, n always ran on regular, so i dont wanna shock the system by puttin a higher octane gas into it. :p i work at a gas station so, its like a $1.17 a LITER here for regular

No, it just changed to that where I live. I guess higher crude prices mean higher refining costs for the different levels... it used to be only 20 cents more for premium, but now it's 30... its bull, but hey, what can you do? Can't exactly stop driving...

Man that seems kind of expensive... a liter is close to 1/4 gal, so you pay, what... $4.50 CND/gallon? Anyone know how CND compares to USD?

With gas at these prices, I would be using the lowest possible octane possible. If not you're just pissing money away. My gas costs $330 to $365 a month. I'm glad I don't have the GTP anymore.

yup 67L is 17Usgal

1.3Lit is 1gal

Yea premium is bad for GTs. Those deposits that can be left by using premium in a regular car can be very harmful and the potential for burning a hole through the piston becomes a possibility.

That's flat out crazy. I only live 7 miles from work so my gas is like $100 a month.

That is crazy... my gas budget doesn't exceed $100 a month... I'm exactly 7 miles from work too, so I fill up every two weeks, and it's usually right around $50 per fillup.

I'm not crazy about how much gas costs me per month with my 70 mile commute. But I manage to work in RI and make the same kind of money I would make if I were a developer in Boston. I had a boston job and it sucks.

I'm glad I don't have the GTP anymore.

Wow...

You are crazy.

Actually, as much as I loved my GTP, there wasn't a month that went by without it going into the shop.

I'm glad I don't have the GTP anymore. I couldn't afford the gas or repairs.

wow.. i live like 1 mile from work... but don't you guys go out? i fill up every week for about 50-60$. ouchy.

As far as octane goes if you use anything higher then whats recommended you are only wasting money.

If your car is recommended for 87 and it runs better on 91 then you have some issues inside your motor.

If your car calls for 87 use it.
If your car calls for 91 use it.

By law the 87 octane has to have the same detergents as the "premium" so your not really gaining anything.

4.50 CDN is like something like 4.15 US I think

I use regular like it says in the manual for an SE. I use shell gas which is suppose to clean the carbon deposits. Is that true about shell gas. I use premiem gas in my se couple times and I started to hear this knock on the left side and had to get that fix and man that was expensive so don't use premiem unless you have a GTP.

I spend about 150- 200 dollars and month. Gas prices here are 3.14 for regular and every fill is about little over 40 dollars plus I go to school and work which is 30 minutes from home.

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."