First bad tank of gas (I think)

Joined
Oct 30, 2015
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835
Location
Wisconsin
On a road trip a few weeks ago, I stopped at a gas station in a smallish town in northern Arkansas. The station wasn’t busy whatsoever (I was the only one getting fuel for the few minutes I was stopped) or very well-maintained, but was of a major brand associated with a big oil company, so I figured it was good enough and didn’t want to hunt around for something that looked nicer as I was on the road all day. (Plus I’d never had a bad tank of fuel from anywhere, let alone this major brand.)

I pumped in a full tank (13-14 gallons out of 17) and pulled out. Down the road, I noticed a super strong vibration when the car was stopped in gear (at a stoplight or similar), which mostly calmed when in neutral. The vibration was strong enough that it actually made sitting in the car at a stop unpleasant - the steering wheel was visibly shaking if stopped at a stoplight or something. It didn’t ever stall but it wouldn’t have been a surprise based on how poorly it was running at idle.

I started researching causes of this, and was thinking I had a mechanical problem of some nature.

But by the time I made it home, two tanks and a few days later, it felt mostly back to normal. I ran a few more tanks down to empty and refilled, and used some Techron, and now it feels completely back to normal, with no unusual vibration whatsoever (some six or so full fresh tanks of fuel later, but it took much longer than just that one tank for it to feel back to normal). I’ve made a conscious effort to use busy stations and to run it lower between fills than I normally might to get the last traces of the gas out.

Strangely, the mileage on that tank was on par with the rest of the trip, over 34mpg, including substantial amounts of mountain driving and some city driving, so it wasn’t like I was getting terrible mileage on the fuel in question.

Any ideas what I bought - a tank of watery fuel? Old and super stale gas? E-85? Diesel contaminated fuel?
 
Joined
Jan 1, 2003
Messages
2,460
Location
Daytona Beach
We used to call that a cross drop. Somebody put some diesel fuel into the gasoline tank. Been some reports lately on Google news. Not likely intentional, but with the cost of diesel going up, I'd say some stations aren't selling their normal amounts.
If the ordering software won't account for that, the truck driver isn't going to haul it back. Even if he does haul back the partially full compartment, he still has hoses full of diesel fuel to get rid of. Where do you think it's going to go?
 
Joined
Jul 1, 2013
Messages
2,741
Location
Ottumwa, Iowa
We used to call that a cross drop. Somebody put some diesel fuel into the gasoline tank. Been some reports lately on Google news. Not likely intentional, but with the cost of diesel going up, I'd say some stations aren't selling their normal amounts.
If the ordering software won't account for that, the truck driver isn't going to haul it back. Even if he does haul back the partially full compartment, he still has hoses full of diesel fuel to get rid of. Where do you think it's going to go?
Who ever does something like that doesn't truck fuel for much longer.......
 
Joined
Apr 9, 2008
Messages
15,981
Location
Central NY
I got a bad tank of gas from a Stewart's years ago. Ended up having to change the fuel filter multiple times. Including once on the side of the road.
 
Joined
Nov 24, 2003
Messages
3,415
Location
Middle of Iowa
Not likely !
it cleared up on its own , bad coil stays bad !

Depends on temperature...

If you are running in a hot climate, it might make a marginal coil perform poorly...back to a moderate climate, more engine bay air flow, etc...and it might return to normal. You could still be on borrowed time if it is a coil.

I will say if it was a coil, all the cars in your signature should be new enough to throw a misfire code if raw fuel were being dumped into the exhaust.

No codes? Probably bad fuel like you guessed, or a chunk of debris from the fuel system that temporarily clogged an injector. You still have ignition in that cylinder, just poor burn.
 
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