What'* with people using 87 or 89 instead of 91/92 around here??? The car needs to run Premium fuel people! Only the new '04 and up Grand Prix'* with the L32 motor can run less then Premium and have it be ok according to the factory. Stop being cheap! Do the math one day and you'll find out it'* really not all that much......
and as far as possible issues arising because of using midgrade or less? How about continuoas stress on the pistons, causing hair line cracks over time, eventually leading to piston failure.
2003 Granite Metallic SSEI 14.5@96
3.5 pulley, Intense PCM, 180 stat, Autolite 104'*, Intense FWI, Borlas, custom Y and chrome Tips, Aeroforce Scan Gauge, MBQuart HU, 12" Power Acoustic Sub, XM Roady XT, Silverstars
(former GTP owner)