Bad tank of gas?

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I've heard about people saying they got "bad gas" but I never really believed such a thing existed, until today. Filled up at BJ's this morning and now my idle seems rougher. Car ran perfectly fine before gassing up. I'm surprised since this station sees a lot of traffic and is well-maintained. Guess I'm stuck until I run down the tank to empty.
 
Or progressively fill-up at 1/4 or 1/2 tank of fuel with "known-good" fuel, rather than waiting to burn through it. Adding some fuel additive may help too.
 
I would say put a can or two of Seafoam in there.

I am fully aware of those who say its snakeoil and [censored], but..It should help neutralize possible water.

Bad gas is for the unlucky few, but does happen, and has happened to me. I had to change a fuel pump over it.
 
Maybe no ethanol was added and thus the octane was low. I would stop back at the station and tell them what happened, ask if any other customers have complained.
 
A few months back I fueled up with premium at a no ethanol added station. My car would not start on first try. Turn it over and wait 5-10 seconds then it would start and run fine. I did not take it on a trip thinking a fuel pump or something must be going on. Then I fueled up with regular fuel and it was fine after that and is fine now. Must have been bad gas. I have used 10+ year old gas that never gave me this much trouble. Dilute it with better fuel and you should be fine.
 
I'e never heard of a bad tank of gas. I think i would look elsewhere for your problems, if there is in fact a problem.
 
Originally Posted By: mclasser
I've heard about people saying they got "bad gas" but I never really believed such a thing existed, until today.

It's rare, but when it happens, it can be a royal pain. When it happened to my Audi, it was very obvious.

I drove up to the station, all was fine. I filled up. I left. A few minutes later it was running bad, particularly at idle, needing my foot's assistance to remain running. I burned it all out, well, as much as I could, suffering through it. I filled up elsewhere from almost empty, and a couple minutes after leaving, all was back to normal.

We did run into some substandard gas with the cabs, too. Most of the years were on LPG, though, so it wasn't a big concern.
 
I had a recent experience with a lousy batch of gas. The idle was a little shaky. The fuel economy dropped dramatically. Soon after I added some mid grade and all was good again.
 
Originally Posted By: bvance554
I'e never heard of a bad tank of gas. I think i would look elsewhere for your problems, if there is in fact a problem.


Man, me neither. In nearly 39 years of driving I can honestly say I've never gotten a tank of "bad gas".
 
Originally Posted By: kschachn
Originally Posted By: bvance554
I'e never heard of a bad tank of gas. I think i would look elsewhere for your problems, if there is in fact a problem.


Man, me neither. In nearly 39 years of driving I can honestly say I've never gotten a tank of "bad gas".

I've only gotten one, in Medford, Oregon, and at a Chevron station. Truck lost power, milage went way down, would ping on the hills, and the normally spotless exhaust carboned up.

Most, if not all "bad gas" is due to the tanker dumping diesel in the gasoline tanks.

Ed
 
It could be worse and have them dump gas into the diesel tanks, which cost a Co-op station in Calgary a pretty penny a few years back.
wink.gif
 
Originally Posted By: Garak
It could be worse and have them dump gas into the diesel tanks, which cost a Co-op station in Calgary a pretty penny a few years back.
wink.gif

Ouch, how many diesel engines did they have to pay to get rebuilt from that?
 
A former neighbor owned a Mobil station in the area, older place but I decided to use it as a favor to him. Stopped there once with my RAV4 (which ran fine on 87) and my car ran like crud on that tank, felt rough and shaky until I filled up again. Stopped there a couple more times over the next few years when I was really low and it was convenient, same bad feeling driving the car.
The neighbor sold the place and retired, the entire station got redone all shiny and new. They also dropped the prices dramatically, stopped by again...and my car ran like crud again. This was so odd to me because Mobil is usually one of my favorites...I don't know if the place has leaky old tanks with lots of water and they were not replaced during the remodeling? There is also a very cheap Irving station in my area that I will not patronize anymore after having my cars (RAV4 and FXT) run poorly after each fillup there, the whole place is less than 5 years old.
Think I told this story here in another thread, there was a really funky little no-name station near a previous job that was really old and required you to go inside first to use CCs. I went there a few times and my RAV4 felt more powerful each time, but I got horrible mileage. Somebody suggested that maybe they were using much more than 10% ethanol...
 
Last edited:
Originally Posted By: kschachn
Originally Posted By: bvance554
I'e never heard of a bad tank of gas. I think i would look elsewhere for your problems, if there is in fact a problem.


Man, me neither. In nearly 39 years of driving I can honestly say I've never gotten a tank of "bad gas".


You have been fortunate and blessed. A BP station in nearby New Castle appeared in the paper a couple of times for having water in their tanks. Some customers cars wouldn't start and run it was so bad.

I had a tank of bad gas once. Years ago, around 16 or so, our family went on vacation in the UP of Michigan. We rented a cabin on a small lake. Since we were out in the country, so to speak, when we ran low on fuel we stop at an old country gas station. Not sure if was water in the fuel, old gas, or maybe rust from old tanks, but our SUV ran terrible shortly after driving away. Ran sluggish and rough, felt like it was misfiring.
 
"Bad gas" can be a misnomer, but it's an easy catch-all for anything to do with a particular purchase of gasoline that causes temporary degradation of engine performance.

In hot, humid climates the e10 gasoline can undergo phase separation, allowing water to be separated out from the fuel, and when you try to burn that in an engine it will let you know things are not right.

As someone else mentioned, there can be an issue its the ethanol to gasoline ratio being off, resulting in fuel with too low octane being pumped into your tank. That can occur at delivery due to human error or when you pump it due to gas pump malfunction.

There are other scenarios involving possibilities of varying degrees of likelihood, but regardless of the cause, your best bet is to add a bottle of Heet to the tank (to mitigate any water that might be present) and dilute the gas with new gasoline as much as possible. Every time you burn a quarter of a tank, fill it up again to keep diluting the original gasoline.

Eventually it should get back to running normally with no permanent effects left lingering.
 
i got a tank of diesel in the car in my sig once even though I pumped regular unleaded. car died the next morning in my driveway. the gas station admitted to the fuel tank delivery driver mixing up the tanks underground right before I fueled up there.


It DOES happen.
 
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