Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Cylinders misfire upon fill-up

I have an '04 Subaru Forester which sputters and stalls after fill up. It sends error codes for cylinders 1, 3, & 4 misfiring…I only have a 4 cylinder car - help! This only started Friday - a few days later and I’m really getting desperate. I screw my gas cap on, we check the connections…and we’ve read all kinds of random solutions that spread across the board. Does anyone have experience with this?

This very often happens because of an ongoing tendency to overfill the gas tank. Many people will continue to pump gas after the automatic shut off triggers. This overfills the tank and can saturate the car’s evaporative emissions system. This carries the gas fumes from the tank to a storage canister where they are sent to the engine to be burned. You are probably ending up with liquid gasoline in there rather than fumes. This is flooding the engine when you try to start it.

take a look on the vacuum diagram under the hood. Just follow the rubber hose from the EVAP to the air intake, disconnect a it at the air intake (cap the end on the air intake) and see if the problem goes away. If does, you will need to service the EVAP. Is your check engine light on ?

I don’t usually overfill although I know I did the last time and I had worse trouble than the prior 2 times; I’ll have to watch how much gas goes in.

Yup, it sure is and it came on around the same time (if not at) the trouble started. No one seems to think the two are linked (but of course those are most of the codes coming up…). I’ll take a look at that and report back. Thank you!

When you report back what you need if you want help is to report the actual error codes - they look like “P1234.” What someone said they mean or something is no good - just the specific codes. I’d bet they are evap system codes but there are a lot of those.

Try just going to 3/4 tank for a while instead of going to automatic shut off and see if that helps.

How long after refueling before the problem clears up?

Will do - I’ll get those for you tomorrow.

The next time I drive I am fine - it’s only when I try to start after fill up.

This is kind of problem is obvious. You should check your timing belt. A timing belt, timing chain or cam belt is a part of an internal combustion engine that synchronizes the rotation to prevent a misfire.

If this happened just once, after a single fill-up, I’d guess the problem is you got a tank of contaminated gasoline… Mabye it had water in it for example. Was this the station you normally use, or one you seldom use? In any case, go back to the station and ask if there’s been anyone else asking about the same thing. They filled up and immediately their car ran poorly. You could also ask a shop to draw off a sample and see if it settles into layers, a sign of contaminated gasoline. Another possibility is you accidentally put in diesel instead of gasoline. Usually a complete refill of diesel the engine wouldn’t run at all, but if you put in say 1/4 diesel into 3/4 tank of gasoline it might still run, barely.

I am sure by now the OP got the car started.

1 Like

If it hurts don’t do it, if you know you need 12 gallons stop at 11, workarounds, stuff that works.

This forum format makes pulling up old, long-dead threads very easy.
I’m disciplining myself to watch the dates, but newbies like nenlish820 don’t have the luxury of having been through the relevant discussions. Nenglish, I implore you to please watch the thread dates. Answering someone’s question 7 months after they’ve left the building really just clogs the pipes up. :slight_smile:

Do you feel it is necessary to give someone a scolding 2 months later? I don’t see how this helps you keep the treads in order.

Nevada, I think you and I have an entirely different understanding of what a “scolding” is.

And I never said it would help me in any way whatsoever. Do NOT put words in my mouth or spin my words.
Or did you just feel the need to try to scold ME!! If so, don’t bother. I don’t intimidate that easily, and your attempt to discipline me is not appreciated or respected. So knock it off.

End of discussion. :imp:

1 Like

How did this discussion turn from misfires to tires?


1 Like

Someone bumped this thread after two months of inactivity to tell another to stop bumping threads.


1 Like