P0304 and I’m probably an idiot.

Hello everyone. I’m new hear and after searching the forum I couldn’t find what I was looking for so I’m reaching out to all you.
2018 SR 4cyl ~35k
Long and short of it:
Let a buddy borrow the truck with (according to the computer) about 35 miles before empty. Being the pal he is, he put about a half tank in it from the gas station I usually go to (76). The next morning I go to start it and it starts ROUGH and throws a code (P0304: “to many misfires within a predetermined period of time” - courtesy of O’Riellys”. After a few seconds though it seems absolutely fine but of course the code stays on. I figure bad gas so in my wisdom decide to fill the rest of the tank with the fancy stuff in an attempt to, well…
I clear the code to see if I can get it to retrigger but after 20/30 miles still no code. The thing is on the hwy the on board “miles to empty” looks like I’m loosing a mile for every 1/2 mile I drive. In town it seems a little off too but not that bad. The computer also just told me I’m getting just over 20mpg combined on a 15 mile drive (hwy&city), which is about what I was getting before all this.
So the question. Bad gas and just burn through it? Do I believe the code and get new coil(s)? Guessing it could even just be a spark plug or two.
Anyway, thanks for reading that long a$$ post, and I look forward to hearing what y’all think!

 

Is the truck running okay now with no codes being thrown? If so then drive the damn thing.

 

No code?

I would wait before sinking money into it. Maybe take a long drive and get more good gas into and hopefully dilute more of that possible bad gas.

 

Nope, no new code and that was actually my plan. I just wanted to check in you all of you who are more intelligent than myself to make sure I’m not doing something incredibly stupid.
Thanks.

 

Then, you got the wrong guy here....

 

might want to throw in some good (not $2/bottle crap. edit: lol i guess it's $4/bottle now) injector cleaner.
you could probably take a look at trims and see excessive fuel use. i had same with a different vehicle for months.
I thought i had a vacuum leak and did exhaustive analysis (for me) because i really did not want to take things apart needlessly...and came to conclusion an injector might be sticking (and compensated for by ECU trims...horrendous mpg... and throwing misleading codes). dumped in injector cleaner and cleared up in one tank.
easy and worth a try.

 

Did u ask him what fuel he put it ? .

 

friend did not fill it...added 1/2 tank. OP filled it after tat.

 

Didnt top off and I’m guessing he go “regular” (off the top of my head 87oct(?)?). The same stuff I get.

 

Might have been bad gas then …had that happen with some chevron gas . Ran ruff even stalled after starting it . Just burn off the bad gas add a higher octane once u have room for some better fuel .

 

Ignore the "Miles to Empty" - it'll self adjust over time. Besides, the best gauge for when to fill up is the one in the lower right of the instrument panel.
As others have said, could have been bad fuel triggering the code.

 

disconnect battery for 10 mins and drive it

 

If you cleared the codes, AND it has NOT returned, AND the truck runs fine. I would not do anything.
Wait and see if it returns before spending money.

FWIW, I'd think bad gas would cause more than one cylinder to misfire.
But again, I wouldn't do anything until the code returns or the truck runs rough again.

 

run it till it does something else.

my truck has hiccupped like that twice, like the computer gets confused how to make the engine run. mine is entirely unrelated to weather, gas fill, or level. i shut it off, then back on, and it works like normal again. damn computers.

 

Lesson learned, "Don't let cheap ass friend use truck"

 

They’re three things to never trust a friend with your car, your money or your wife.