I have heard of many people having performance problems when they tweak their software (i.e. Dinan Performance Engine Software) and then use cheapo gasoline (hard to believe huh?, it was for me too, why anyone would use cheap gas in such a car)...FYI... from the Owners Manual and then list of Top Tier Detergent Gasoline Retailers:
From the N.A. Owners Manual
Super Premium Gasoline/AKI 93
Always use this premium grade fuel to obtain
maximum fuel economy and performance.
The minimum approved fuel grade is AKI 91.
Do not use gasoline below the specified
minimum quality, as otherwise engine
damage can result.<
Use high-quality brands
Field experience has indicated significant differences
in fuel quality: volatility, composition,
additives, etc., among gasolines offered for sale
in the United States and Canada. Fuels containing
up to and including 10% ethanol or other
oxygenates with up to 2.8% oxygen by weight,
that is, 15% MTBE or 3% methanol plus an
equivalent amount of co-solvent, will not void
the applicable warranties with respect to
defects in materials or workmanship.
The use of poor-quality fuels may result in
drivability, starting and stalling problems
especially under certain environmental conditions
such as high ambient temperature and
Should you encounter drivability problems
which you suspect could be related to the fuel
you are using, we recommend that you respond
by switching to a recognized high-quality brand
such as gasoline that is advertised as Top Tier
Failure to comply with these recommendations
may also result in unscheduled maintenance.<
TOP TIER Detergent Gasoline Retailers
Gasoline retailers must meet the high TOP TIER standards with all grades of gasoline to be approved by the automakers as providing TOP TIER Detergent Gasoline.
In addition, all gasoline outlets carrying the brand of the approved retailer must meet the TOP TIER standards.
Additional gasoline retailers are added to the TOP TIER list as they meet the standards. The retailers known to be on the TOP TIER list are shown below.
TOP TIER Gasoline Retailers:
MFA Oil Company
Kwik Trip/Kwik Star
The Somerset Refinery, Inc.
Tri-Par Oil Company