Whenever I heard someone say they got a bad tank of gas, or told someone to avoid a certain gas station or chain because they sell bad gas, I thought it was all in their head. In all my time driving, I have NEVER experienced anything resembling a tank of bad gas. That is, until a few days ago. I filled up at Wal-Mart / Murphy USA and immediately after filling up - and I do mean IMMEDIATELY - my car started doing this weird jerk. As I was pulling out of the station, it seemed like it was either misfiring or shuddering, just once here and there, but each time it occurred it shook the whole car. It kept doing it intermittently throughout my lunch hour. It wasn't really noticeable at speed i.e. while moving; it only seemed to occur while stopped at a light with the trans in drive. As the day progressed, and through my hourlong commute home, it went from intermittent to being regular. At that point, stopped at a light, the car would "jerk" about every 20 seconds or so. Each time it jerked, it felt like a really bad misfire, as if the engine was going to cut out. But it never did. Boy did it make me nervous though.

The next morning, I was backing out of the garage as usual. I normally start the car right up, put it in reverse, back out of the garage, and then idle for a few seconds to let the engine warm up. Our 20 x 20 master suite is above the garage, and I don't like the thought of gassing my wife as she sleeps, so I idle outside the garage before leaving. Except this time it stalled when put into reverse. I put it back in park and cranked, and nothing. Had to crank and crank and crank and then it finally caught, but very weakly. This was scary now. I let the car warm up for about 5 minutes and, having no choice, drove it to work. Once again, a nerve-wracking commute as the car kept shuddering and misfiring, leaving me to wonder when it was going to stall on me. But again, it never did this at speed - only while sitting stopped with the trans in drive.

After a few days of putting up with this, I put two and two together and decided that maybe it was in fact the recent tank of gas causing the problem. Did some research on this board in the past and had read a lot about Techron, so I took a chance, picked some up yesterday at lunchtime with about 1/8 to 1/4 remaining in my tank. Dumped the whole bottle in there, then put $10 of gas in (about 4.5 to 5 gallons). Then I proceeded to drive it like a Formula One car, very hard. Throughout my lunch hour, it still did the same stumble/misfire thing. But here's where things get interesting. On my drive home, although it continued to jerk, it did it a little less. By the time I got home, it was jerking only about once every minute or two when stopped at a light. And the jerks weren't as severe.

When I got home after work, I put the wife and kids in the car (rather than use the minivan) and we drove it to get some things done. Through the drive, the jerking kept decreasing in frequency and intensity. By the time we got back home, the car seemed to be *mostly* back to normal. I say mostly because the jerking was gone completely, but the car seemed to idle slightly rough, whereas it used to be pretty smooth. On a scale of 1 to 10, it used to idle at about a 9, but now it was about a 7.

Driving to work this morning, same story. Idling at about 7 to 8 (not perfectly smooth), but no stalling, jerking, or misfiring. The few gallons with the Techron in them are almost entirely burned up, and I will have to fill up again once I get home.

Here are the questions I have:

1) Do you think my problem was caused by bad gas?
2) The tanker was filling the station up when I was there. I've heard theories that this is a bad time to fill up since it stirs up impurities in the underground tanks. Is there any truth to this?
3) Did the Techron actually cure my problem or was it coincidence since I had mostly burned off the "bad" tank of gas?
4) Do you think this was just a freak thing and is gone, or will the problem come back?
5) I have filled up at the same station here by my workplace for nearly a year and have never had a bad experience. The few gallons I put in for the Techron came from this same station, and I plan to continue using the same station unless this problem occurs again. Am I stupid?

Thanks everyone.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Although there are combustibles in it, Chevron's Techron is primarily a detergent/solvent, not an octane booster.

There are occasions of bad gas being distributed by refineries, typically at lower cost stations that sell "base gasoline" which is the basic refinery fuel. Other brands use the base gasoline with their own proprietary additives/detergents to create their signature fuel. Last year service stations at certain Costco/PriceClub were hit with a big batch of off fuel.

Underground fuel tanks have filters, as does your fuel tank that would catch "particles."

And finally, a lesson for life . . . never overlook the power of coincidence. Just monitor your cars performance over the next couple of tankfuls.

sometimes when a tank is being filled it does stir up the junk. But, they do have filters. However, low tanks are subject to greater surface areas which can lead to condensation and the addition of water to the fuel. So, you might have had a combination of crummy fuel (you did buy at a walmart, the captain of crummy) and/or a bit of extra water in the fuel. the fuel and water would not mix properly, so you'd have a splash blend. Over a little bit of time, it would separate, and you'd get uneven running for a time, but not neccessarily the entire tank, depending on where your fuel pick-up is located.

__________________
Cannondale ST600 XL
Redline Monocog 29er
2011 Mini Cooper Clubman
2005 Honda Element EX

www.djugurba.com
www.waldenwellness.com

1) Yes, "bad gas" is usually due to water contamination

2) Yes, It is good practice for the station not to use a freshly filled tank for at least one-half hour, but I suspect this rarely happens in practice. Filling the tank can stir up water at the bottom of the tank and allow it to mix more with the fuel, but it will settle out to the bottom with time.

3) No, Techron is probably the best product on the market to clean deposits off injectors and inlet valves, but it will not cure a water problem. Ethanol is a "co-solvent" which will allow separated water to mix uniformly with gasoline and in such low concentration, it will not cause driveability problems. The problem probably self corrected due to the water being purged from the system by the normal consumption of fuel. There are also commercial "gas driers" available at auto parts stores, which contain ethanol. If it ever happens again, try one of them.

BTW, is your fuel "oxygenated" with ethanol? Most areas of the country require oxygenates in the winter, but not summer and March is usually the changeover period.

4) Probably just a freak occurance, but try to avoid filling up when you see a tanker unloading.

5) I would suggest you talk to the station manager and tell him about the problem. Ask if they allow the tanks to "settle" for at least a half-hour after a fuel delivery before the fresh fuel is made available to the pumps.

Duke

http://www.toptiergas.com/

__________________
Kent Christensen
Albuquerque
'07 GL320CDI, '10 CL550. '01 Porsche Boxster
Two BMW motorcycles

This doesn't surprise me at all.

I live in a small town that has a Wal-Mart Super Center. I had a conversation not long ago with the owner of a local independent garage. He went on to tell me how he had gone thru a slew of cars being towed in over a 2-3 week period of time. The gas tanks on all of these towed vehicles had white milky looking whatever in them. Same question was asked of all owners - where do you buy your gas? - same answer - Wal-Mart.

There is a reason why WM is cheap and you often times pay for doing business with this kind of company.

__________________
'91 300-SEL

Greetings ShopForum,

Regarding the topic, you are more likely to ignite a holy war than hear objective advice. My personal experience with the BG product line (44k and fuel injection cleaner) in several vehicles during the past four years has been very positive. I also intend to give the Auto-Rx (http://www.auto-rx.com/) engine cleaner a go in the near future.

These have been stated in different ways by other respondants.. but here are some good rules to live by:

- Choose stations that are frequently refueled (i.e. close to a highway exit).
- Always choose a station associated with a well-known brand (Shell, Esso, Chevron, Amoco/BP, etc.). Base fuel is often sourced from a single refinery for a region, but detergent quality really does make a difference.
- Rotate between at least two brands every other month or quarter.
- Do replace your fuel filter(s) on schedule and routinely check your fuel lines for leaks.

- Avoid stations at the bottom of a hill or in a valley -- these tend to have greater risk of contamination during rainfall.
- Avoid stations with older pump equipment, and thus older storage tanks more susceptible to contamination. Just ask me how I learned this valuable lesson :-(
- Avoid fueling your car while the tanker is fueling the storage tanks, old wives tale or not.

Just my humble opinions,
-DM

__________________
1995 E420 SE black/black
2004 Volvo V70R AWD

What causes the gas to turn into that white milky stuff?

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

Warren:

I haven't a clue. It sounds strange to me, but I've known the owner of this shop for about 15 yrs. - not one to fantasize.

He saw this on about a half dozen cars. All were towed in. All of the owners claiming they had been buying gas at the local Wal-Mart.

Who Knows.

On a different note, WM sells brand name tires..ie.. Good Year, but try getting a warranty issue on one of these tires resolved at a Good Year dealer. They are made by Good Year under contract for WM. Not the same quality as regular Good Year.

Who knows who they get their gas from or what quality controls are/are not being used.

__________________
'91 300-SEL

Your post really has nothing to do with Techron.

Odds are you got water in your gas. Happened to me as well.

Owner of station was combative, and claimed that this was "impossible", and yet there was the water. I didn't even want anything from her, just thought they would like to know there was a problem.

I pumped out the tank, then drained the residual. Then I let the water settle out, and poured the gas off the top for reuse.

__________________
1986 300E 5-Speed 240k mi.

Water.

The gas isn't "bad" or "cheap" at these places, the management is just cheap/lazy. They have procedures for draining condensation (water) out of their storage tanks. The bozos running these stations just aren't doing them. Complain and/or buy elsewhere.

BTW, this has nothing to do with octane rating. It's just that water doesn't burn too well. Luckily, with most fuel injection systems, the gas flows past the injectors and back to the tank, so you get enough circulation of gas to let the car keep running. In a carburated engine, the gas would accumulate in the float bowls and you'd be stuck until you disassembled and drained them.

__________________
Norm in NJ
Next oil change at 230,000miles

Could it be possible that the rough running conditions caused a motor mount to collapse which, in turn, is now causing the rough idle?

Also consider some stations carry a layer of water at the bottom of the stations' tanks (above the pick up pipe) so they do not pay for idle inventory. They adjust the water level with alcohol. If they do a poor job you get water in the tank or over alcohol. If you wonder how you have melted fuel hoses, now you know. Impossible to prove.

Stick with stations that have service garages. Less likely to employ cashiers who double duty as fuel adjusters.

97dieseldriver
Although I only spent over 25 years of my life working for 3 different major oil companies operating thousands of service station, I have never heard or seen any of what you are talking about.
Water is kept at a minimum level and pumped out when it reaches a pre-determined level, depending on the size of the tank and the addition of alcohol is strictly forbidden.

BG44K is the best stuff money can buy....................

__________________
Proud owner of ....
1971 280SE W108
1979 300SD W116
1983 300D W123
1975 Ironhead Sportster chopper
1987 GMC 3/4 ton 4X4 Diesel
1989 Honda Civic (Heavily modified)
---------------------
Section 609 MVAC Certified
---------------------
"He who fights with monsters might take care lest he thereby become a monster. And if you gaze for long into an abyss, the abyss gazes also into you." - Friedrich Nietzsche