Jun 1, 2020



Some bad news our tuners here at ZZP stumbled on - and it explains some issues we've been seeing first hand. Unfortunately, due to the worldwide pandemic, the EPA has loosened their regulation on the fuel grades being shipped to our stations.


Ticket #PIP5725: EPA Summer Grade Gasoline Waiver Allows Use of Winter Grade Surplus Potential Drivability Concerns P0300 P0171 P0174 P228C Fuel Smell Odor Longer Extended Cranking Time Hesitation Engine Stalls - (May 8, 2020)

Condition: In rare instances some customers may complain about a fuel smell / odor, longer starts, hesitation and under extreme cases, engine stalls. Technician may also find any combination of DTC's P0300, P0171, P0174, P228C set.

Cause: The ongoing Coronavirus (COVID-19) pandemic has caused significant reductions in driving and fuel use. Due to the surplus of winter grade fuel sitting in storage (pipelines/stations) the EPA is waiving the fuel vapor requirement. This will extend the use of winter fuel into the summer months. The use of winter fuel in summer weather may cause drivability concerns. This should not be single events but should be multiple occurrences associated with hot days.


What does that mean for car people, especially on a TUNED or E85 car?

  • Stick to your NAME BRAND fueling locations: (IE. Speedway, Shell, Mobile..) This will usually give you the best bet at higher octane, as bigger chains generally have stricter fuel standards.

  • Monitor as many parameters as you can. We here at ZZP recommend and all use an AeroForce, which comes with the ability to measure fuel trims, knock retard, and scan for codes. This is especially important on a non-flex E85 car, or a tune running a blend of fuels. However, if this is out of your current budget, you can pick up some E85 testers which you can use at your favorite gas stations to confirm what you are getting before you continue to run their fuel. Some other parameters we recommend watching if possible are misfires, Lambda (if your car has a factory wideband), or any other Knock sensing measure. You want to avoid knock as much as possible - this is hard on an engine.
    Check out our AeroForce options here:
    We also sell some AEM guages, guage mounting pods, and accessories to set up your ride for constant logging and monitoring.
  • If you're having any issues with your car running, idling, making power, or cold starting, start your diagnosis by checking the fuel. Try finding a way to test your fuel grade or switch stations - this may be entirely your problem. If you are having issues, DO NOT floor your car. Keep your forced induction car out of boost, and generally refrain from anything more than regular "commute" style driving until you can find and swap to better fuel. If you're still having issues, contact your tuner and we here at ZZP are always happy to take a look at your logs and help dial in your build.

  • A tuned car or a performance oriented car in general is going to be much more sensitive to changes like fuel grade, temperature, altitude, etc. On a common stock car, this fuel crisis will probably have zero affects. But for us car enthusiasts, we want to keep our rides running perfectly, with the best fluids possible for healthy, long-term power.