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Can I run premium fuel in my 99 GT?

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09-16-2009, 05:58 PM

#21

mrsinister2424

3rd Gear Member

Join Date: Dec 2008

Location: CA

Posts: 588

Just get your car dyno tuned to 91, then you HAVE to run it.

09-16-2009, 08:53 PM

#22

98redstang

5th Gear Member

Join Date: Mar 2008

Location: NJ

Posts: 2,312

Quote:

Originally Posted by mustangman03

Sorry dude but you are wrong i have had a car i ran both 87, 89 ,and 93 and i got the same fuel economy. the fuel doesnt burn any cleaner either that is in the quality of gas not the octane rating. the octane rating is how slow the gas burns in the cylinder, 87 burns faster than 93. So there is no benifit from running 93 over 87 unless you have a tune for 93, Forced Induction, or higher compression. Now as far as which brand of gas to use i dont know but i like trying to find somewhere that doesnt have the 10% ethonal because it doesnt get the fuel economy as straight gas.

+1 I commute to school everyday and i use mid grade. I get close to 20 and thats with some screwing around. It mainly highway. But switching grade didnt do anything for me. I just ran mid grade to keep the motor cleaner and because of the high compression it runs better. It ran like crap on regular.

09-22-2009, 04:47 PM

#23

fordmuscle

Join Date: Sep 2009

Location: Gulf Coast

Posts: 13

As far as running 93-octane fuel you’re fine. Your second question about running the a/c, and it feels like its pulling power at weird intervals?? I think that issue is caused because of the compressor cycling on and off.

09-23-2009, 02:04 AM

#24

99gtstang08

1st Gear Member

Thread Starter

Join Date: Apr 2008

Location: Missouri

Posts: 60

So I cleaned my MAF sensor and IAC this weekend and it took care of the idleing problem. It made the car run better in general it sounds better and feels stronger. Everyone should do these two things when they do a tune up. I also filled up with 87 on friday and I am already half empty again. I dont think the octane has any thing to do with mpg but it is crappy coincidence.