I understand that this forum will jump to tell me all of the crap I did to my engines or all the money I wasted...even if not intended I have a feeling the answers to this will be harshly aimed at me and at the EPA, etc.
I have two cars which I have tried unleaded 88 gasoline in for a few months. A 2014 Buick Encore (1.4l turbo) and a 2015 Chevrolet Sonic (1.8l). The Sonic, with about 45k miles, ran perfectly fine for the past 2 months or so on 88. The only thing I noticed wrong was I was averaging 2mpg less than normal -- 32 to 30 -- so I didn't think anything of it. I tried 88 once in the Encore on a trip across the state and when I got home after a few days the check engine light came on. Now, I know everyone would jump to point fingers at the gas, but about 3 months ago, I had my oil changed at the dealer and they screwed it up and double gasketed the filter, causing it to blow off and splatter oil all over my engine. I ran my OBD2 scanner, which led me to the MAF sensor which when I took it off was covered in oil (this was after the gas). I replaced the sensor and now there are about 3 other codes. Also, now my Sonic is showing an EVAP sensor code but it has been running fine for weeks!
I think it is easy to blame it on the gas, but the oil change could have done much more damage than I thought.
Any thoughts? Thanks!
I have two cars which I have tried unleaded 88 gasoline in for a few months.
Why would you deliberately use the wrong fuel???
I had my oil changed at the dealer and they screwed it up and double gasketed the filter, causing it to blow off and splatter oil all over my engine.
Servicing a car at a dealership when it's out of warranty offers no advantage in price or quality compared to using an independent mechanic. Stick with using the recommended fuel and find an independent shop/mechanic instead.
The E15 gas will eventually do some kind of damage but it will probably take some time. I frankly don't see where it's worth the risk, but they're your vehicles.
I expect your mixture is somewhat off since the fuel injection is not calibrated for more than 10% ethanol contamination.
had my oil changed at the dealer and they screwed it up and double gasketed the filter
bloody idiots. Can't even get an oil change right. They are absolutely good for nothing. I swear they're no better than a quick lube joint. 
I replaced the sensor and now there are about 3 other codes.
Post them please.
my Sonic is showing an EVAP sensor code
what code?
Can't really help you if you withhold the most relevant information from us.
the oil change could have done much more damage than I thought.
to the evap system? doubtful.
I apologize for not posting the codes:
On the Encore there was a P0496 and a P0420. The Sonic has been fixed and is no longer an issue.
The Sonic has been fixed and is no longer an issue.
ok so our rules is one question or one vehicle per topic. No laundry lists please.
On the Encore there was a P0496 and a P0420
P0496 is a leak in the EVAP system, so check all the hoses and valves, or perform a smoke test if necessary.
https://www.obd-codes.com/p0496
P0420 might disappear after you fix the EVAP problem. If not then you have a an issue with the exhaust system. It's covered in our FAQ.
Posted by: @imperator
I swear they're no better than a quick lube joint.
@hixster it's shameful. They're supposed to have the best training in the industry.
I couldn't help myself.. that's sad and funny at the same time. Saw this on a "Just rolled in" episode this past weekend. The 2 gasket mistake.. omg
that series just makes my jaw drop. Every time.