jishead

I've ran my GT for like 20,000 miles. It's never ran bad in heat, snow, rain, long trips, traffic or any other time. Only time it ran a little rough was when I had my Densecharger kinda installed a bit cokeyed causing stress which seperated a tube from it's flange causing unfiltered turbulent air to suck past my MAF. I corrected the prob and all is well. I hate to hear that folks are having bad Mustang days. Higher octane only prevents detonation caused by higher compression or advanced spark. It will not correct any problem nor clean your engine nor cause it to run better/smoother. I've done tons of homework on it. I run 91 Shell because I have my timing bumped way up via Predator. Running higher octane than neccessary (in theory) causes power loss as it slows combustion. If you find a fuel that you believe to be cleaner or have better detergents or from a more reputable source then that is different and not to be confused with an octane number. We mix up our language (premium/octane). If you have a low compression 4.6 with no timing adjustments, reach for some clean 87 octane!!!

O2GT

well let me tell ya i have been running nothing but 87 for the past 5 fillups(same Exxon Gas station 2.15 a gallon.. and the car runs great .. I TOTALLY AGREE with anyone who says running ANYTHING over 87 on a stock GT is a WASTE OF MONEY it's all in the head.. I have gotten the best gas mileage with 87 .. the only thing i have to say is when i have a 1/4 of a tank.. i hear some pinging but only under HEAVY acceleration. I still have awesome power etc.... but then it stops when it goes past the 1/4 line .. very weird.. BUT it drives fine otherwise

PonyRider98

when I run anything other that 93, my check engine light comes on. I've been running 87, then I tried 89, but then I put in 93, the check engine light went off and the car ran like a dream. With 87, it boged down and ran like crap.

jkm1987

i run shell premium or chevron premium and thats it even before i advanced my timing it didnt like anything but 93 shell and chevron has some of the best gas too

JonBeast

The only reason I run 93 is because of my advanced timing, otherwise I would be running 87 or maybe 89.

marcuslee842

For some reason if my tank is 1/4 full or lower and I get a full tank of gas the engine seems alot more responsive and little bit more powerful. Does anyone elses car do this?