Throughout my career I’ve seen countless cars come to me with various ‘Check Engine’ lights or ‘Service Engine Soon’ lights.  Roughly 1/3 of those cars suffered from bad gas.  The top two offenders?  Costco and military bases (we’re in San Diego, so it comes with the territory).  The first question out of my mouth to most of these customers was ‘Are you buying gas from Costco or the base?’  If they answered yes, I’d clear the light and prescribe a full tank of Chevron and all of a sudden things were back to normal.  Bad Gas.

Hell froze over last March when Costco re-vamped their fuel product by qualifying for ‘Top-Tier’ status. In all honesty, I didn’t discover Costco’s new found love for quality gasoline until my buddy Pat bought it to my attention (he’s a car guy and my go-to beer expert).  After 15 years of warning folks about getting gas from Costco, I can actually say that not only is it OK to get gas from Costco, but that they sell very high quality gas! Go ahead and fill ‘er up!  (I’m twitching a bit as I type that).


Top-Tier Gasoline


Bad gas.  What the hell is bad gas?  This is a discussion that can get pretty technical and I’m not calling in the engineers.  Let’s just equate gas to the beef industry.  Anyone can sell beef, and it doesn’t have to be good, just edible.  But we all know the difference between a prime cut of rib-eye, and the stuff that your dog woofs down out of the Alpo can.  They are both edible, they are both beef, but chances are you’d only put one of those in your tank while your dog doesn’t really care.  Think of gas in the same way.




Top-Tier gas is a standard developed by several auto manufacturer’s about a decade ago.  Modern performance cars started running like shit on cheap gas and they weren’t passing emissions testing because of it.  The cars were running, but due to the poor fuel quality, the fuel injection systems would dial back performance factors like timing and fuel mapping to compensate.  In essence, engines were running at below peak performance and, more importantly, peak efficiency.  Thus, the Top-Tier standard was implemented and adopted.  Here’s a brief video explaining Top-Tier gasoline. If you’ve ever seen the TV show ‘How it’s Made’ I’m pretty sure it is the same narrator.



Initially there were 10 gasoline companies that conformed to the standards of ‘Top-Tier’   The list now is over 30 and below are some of the national retailers that qualify for Top-Tier status:

76 Stations
Costco Wholesale
Phillips 66

Click here for the full list

As you can see, Costco is on the list, and you’ll see the Top-Tier logo at their stations.  So go ahead and buy 40 rolls of toilet paper, enough laundry detergent for a football team, a case of Stone IPA at half the price, and a full tank of gas.

My suggestion, get the gas on a Tuesday night, the line on Sundays will eat up the first half of a football game.

Chris Keefer

Independent Motorcars

5836 Autoport Mall

San Diego CA 92121