Rough idle after getting gas?

Every time I get gas, I get a semi rough idle.

Never any other time besides this... A little water in the tank?

Are you getting it at the same station or any station..

I know gas prices are high right now, but if you're putting in cheap gas -- Arco, Costco, Grocery store gas (Safeway, Hess, Racetrac) you're getting cheap, shitty gas.

 

Shell, Chevron or 76 are really your only options, unless you'd like to pay extra extra for 114+ octane.

 

Cheap, shitty gas can (and will) cause problems and can eventually destroy your motor. Is it worth it to save (literally) a couple of bucks on each tank?

 

You may have also developed a fuel pump or fuel injector issue. Is the problem only occuring immediately after filling up? How long until the problem subsides/goes away? Do you have an AP or the ability to log? (Vagcom/Tactrix, etc)

 

Check your oil level, too. Also, when was the last time your OCVs were changed?

Yea that's what I was getting at. The reason you pay more for gas at a good station is because it's new. The cheaper station buy grade b or lower which is 30+ days old. The longer gas sits it starts to break down and the ethanol absorbs water.

 

Put it this way. You pour a soda in a glass of ice. It's amazing you drink half of it. Walk away get caught up in something come back 3 hours later it's flat and watered down. That's grade b gas. You usually pour it out dont you?

Its Wawa gas, generally pretty good, never have a problem, except for the fill up. They get new gas everyday.

Its immediately at the station, and as soon as I give it a rev it goes away, just that first couple seconds after getting gas. Not sure on OCV, i bought it in April.

I have a accessport, and a ODBII wifi scanner with logging options.

Its Wawa gas, generally pretty good

 

Said no one, ever.

 

From what I understand, Wawa = independent/non-franchised fuel, which means it is NOT of high quality, so as to make it affordable to the shop owners, and competitive to the local market. Furthermore, they're less likely to buy all three grades of gas and only buy 87, but run it in all three pumps at three different prices because there's no oversight or accountability. Five bucks says they don't even speak English and haven't paid taxes in years.

 

See my above comment about cheaping out on gas. If you like the shopkeepers/cute girl behind the counter, buy a pack of gum or an Icee to support them. Your car isn't worth the few cents you'll save by getting gas there, or whatever left-wingnut jollies you get from supporting a local business instead of making The Man richer.

 

Get gas from one of the makers I suggested. Whether or not it'll solve your problem is irrelevant; it's just a good idea.

 

I'd guess that if there's nothing serious amiss or any trouble codes, the ECU is seeing some mixed evap signals and compensating until the learning kicks in and evens everything out.

Seriously? Have you ever been to a wawa. They're like the biggest one stop convieince store / gas in the philly del nj market. They're all English speaking people and I'm sure they pay their (huge) tax bill. This ain't jojo's gas hut. They run 92 which is higher than most 91 around here.

 

 

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Sheets and wawa are grade b gas. I won't put that in my lawn mower.

 

And any station that doesn't sell 93 is a red flag to keep going.

I'll try some non-English speaking shell and see how it runs.

 

 

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Are you topping off the tank to the very top, that's not good to do, some thing about the evap tank canister getting to full.

 

Yea, I agree, with a turbo engine, give it name brand gas, most of the time, like as much as possible.

 

Does WAWA have a name brand label on the gas pump, like Gulf, Sunoco, Shell ? The store I get 90% of my gas at has Gulf. I don't even know the name of the store, I drive by it every day...It's not important, if it didn't have good gas I wouldn't stop there other then to get milk, it's $2.99 and gallon.

It's till the nozzle clicks and they don't top off there.

No it's wawa brand gas, they're a huge brand here so they have their own distribution network it's gotten so big. Diesel too.

Works just fine in my wife's XT.

 

 

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I wonder if you have an injector hanging open on shut off.

 

When you get home, shut the car off. wait 3 minutes, try and start it again. See if it does the same thing.

Will do. Thanks.

 

 

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I seem to recall this problem a few years back...on here.

Wawa sells gas under their own name. Some time ago, Wawa was getting their gas from Citgo (I took great delight in telling a few Neocon cheapskates they were sending their money to Uncle Hugo). More recently Wawa sources from Lukoil. Although I am not aware of any quality problems in the Williamstown area, Wawa sold a lot of bad gas in Ocean County and a number of people had to drop the tank and clean out the system.

I wonder if you have an injector hanging open on shut off.

 

When you get home, shut the car off. wait 3 minutes, try and start it again. See if it does the same thing.

 

But wouldn't a stuck injector throw a CEL, too?

It happens after shut down. No power.

 

The fuel evaporates before the next start cycle which for most is while later.

If its only on a full tank, could it be a bad fuel pump? Perhaps the pressure of the full tank is causing it to sputter or misbehave?

And I drive another 50 miles after I get gas so I'm never FULL except at the pump...

 

 

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I know gas prices are high right now, but if you're putting in cheap gas -- Arco, Costco, Grocery store gas (Safeway, Hess, Racetrac) you're getting cheap, shitty gas.

 

Shell, Chevron or 76 are really your only options, unless you'd like to pay extra extra for 114+ octane.

 

Cheap, shitty gas can (and will) cause problems and can eventually destroy your motor. Is it worth it to save (literally) a couple of bucks on each tank?

 

You may have also developed a fuel pump or fuel injector issue. Is the problem only occuring immediately after filling up? How long until the problem subsides/goes away? Do you have an AP or the ability to log? (Vagcom/Tactrix, etc)

 

Check your oil level, too. Also, when was the last time your OCVs were changed?

 

All gas is refined to the same standards. In many cases Chevron refines the gas for X grad b. From someone in the know, the major difference is the additives IE techron. If you were to run one tank of chevron in your car every 10-15 tanks or drop in a techron 20 gal fuel treatment every oil change the effects would be the same.

 

As it would be, until recently, Shell was using techron in lower doses until they developed a new formula.

 

However, the KNOCK projection on 91oc gas is the same from each station, within the margin of error.

 

 

Yea that's what I was getting at. The reason you pay more for gas at a good station is because it's new. The cheaper station buy grade b or lower which is 30+ days old. The longer gas sits it starts to break down and the ethanol absorbs water.

 

Put it this way. You pour a soda in a glass of ice. It's amazing you drink half of it. Walk away get caught up in something come back 3 hours later it's flat and watered down. That's grade b gas. You usually pour it out dont you?

 

Chevron states their gas can sit for 9-12 months without the need for an additive. I've done it, and then I burned the gas up a WOT at 7-8k on a 11.1:1 motor without a single knock/miss.

 

30 days, you're kidding yourself. Unless Chevron/Shell near you is super busy they don't get their 91 refilled as often as their 87. Want to bet your small town grade a station has 91 oc approaching 30 days?

 

What is a much lager problem with gas is the quality of the tanks. Old stations can have problems with water getting into their system. This is a very easy check though. If you doubt the quality of the gas, put some in a glass container and look for water yourself. It can be seen by the naked eye.

 

Gas is filtered at many points along the way to your injectors as well.

 

What might be more likely for the OP is that they filled the 91 tank with 87. Even then, unless on stage 2, the stock map will run, though with less boost.

 

I'm going to to get flamed. So here goes. I've run my own tests, been good friends with chemical engineers at Chevron and seen the results for myself.

 

Facts:

- Nearly all motors rated for 91 will run their entire lives on 87 without being ruined. Porsche has 12:1 + motors that will do this

- Grade A vs Grade B gas is largely marketing and additives. If you knew how little the difference was between the two you'd laugh.

- Techron works, it's still the best fuel additive on the market doing exactly what it claims

- Of the Grade A companies Chevron gasoline has slightly more energy in it per OZ. Unfortunately the difference falls within the margin of error.

 

My personal experience has been that I've run over 150k on a motor rated for 91oc on the cheapest of 87 oc. Not a single problem. Two other family members at one chevron employee have done the same with nearly 1/2 mill miles on motors that by the igorance of the internet should have exploded.

 

Nearly all motors rated for 91 and not pushing 12:1 + do so for emissions reasons. 11:1 motors do NOT require 91 oc to avoid knocking.

 

Turbo'd motors are a slightly different story with the octane rating playing a larger part in the knock protections; while grade of gas has near zero impact on knock.

 

I wish I had a way to share these studies in detail, but take it for what it's worth. The Grade A vs Grade B debate is like folks who believe oil needs changing at 3K, even in syn, even with normal commuting. It's plain, old fashion, ignorance.

Thanks. These wawa stations are all >5 yrs old. Mine in specific went in 2 yrs ago.

Only real question then is 92oct is really just 87 but of course why market it as 92 over 91 if it's just 87

 

 

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Yes all cars requiring premium will run on regular. That's why the knock sensor is there. It'll retard the timing. Now that being said it can only retard so far. If you get a bad batch of 87 it won't retard enough. With subarus already having ringland issues octane and quality of gas isn't something you should be messing with. You won't always see the results of detonation right away. One day it'll show up.

 

And 9-12 month no additive yea I can see that IN NON ETHANOL fuel. There are time lapse video around of ethanol pulling in water from the air a doubling in volume.

Just wanted to update that I've been using Sunoco gas for a couple weeks but I still get almost immediate stalls or at least a rough idle when starting immediately after refueling, both getting 1/2 tank or getting it filled.

Thoughts?

Its gotta be something in your fuel system. Perhaps has to do with the pressure in the tank after a full tank. Are you topping it off? Gas cap working ok?