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2001 EJ257 Hybrid S 5MT 5MT
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1,932 Posts
Discussion Starter #1
Hey folks, it's been a while since I've had time to browse the forums.

my forester just picked up a really bad bucking problem.

I'll be coasting down the highway, when all of a sudden it feels like someone is pulling at the back of the forester, and i can't accelerate for a few seconds. It's really scary.

it also happens in other gears besides 5th as well, but not as often.

stopping to 1st is pretty bad though.

any ideas on what it might be? I'd rather not have the car just give out on me in the middle of a road trip, ya know?


-Philip
 

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Premium Member
2008 XS 4EAT
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9,878 Posts
Any chance you've picked up a bad tank of gas? I take it no CEL's are appearing. How is it at idling, will it rev freely? I'm going to go with a bad tank of gas, sure others will add more feedback. Good Luck.
 

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2008 LL Bean (4EAT)
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4,909 Posts
My wife filled up her Buick a year ago and it began to buck and cut out. The car barely made it 20 miles to home, was towed to a shop, where a lot of water was found in the tank. The shop gave us a half-gallon of water in a jug, but there was a lot more they didn't bother to save. The gas had to be discarded, the tank removed and cleaned, and the fuel system cleaned. $1000. We notified the gas station and they paid the cost, saying there were a dozen other cars who reported the same severe problem.

But many more cars would not have filled up, and not have practically quit running. They would have taken on less gas and less water, missed and bucked some, and owners would call it bad gas, and drive on through it. Maybe that is what is happening here.

If you think you got "bad gas", best to tell the gas station. It is an accident in their system. Our station said their water alarm system had failed to tell them. They think the water came in the tanker that delivered the gas.
 

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The Modfather
2016 BRZ Limited - Manual 6 Speed Manual
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8,095 Posts
Throw one of the big bottles of Techron in there to start. Also, pull out each plug wire up at the coil pack (one at a time) and inspect the metal contact. If it's not shiny brass, get something to shine it up like emery cloth. If they are black and mungy that may be your problem. Clean them and put some Dielectric grease on the metal before plugging it back in. If it's not that, I'd start to suspect the front Oxygen sensor. How many miles have you got? What's your MPG's been like lately?
 

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2001 EJ257 Hybrid S 5MT 5MT
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1,932 Posts
Discussion Starter #8
Throw one of the big bottles of Techron in there to start. Also, pull out each plug wire up at the coil pack (one at a time) and inspect the metal contact. If it's not shiny brass, get something to shine it up like emery cloth. If they are black and mungy that may be your problem. Clean them and put some Dielectric grease on the metal before plugging it back in. If it's not that, I'd start to suspect the front Oxygen sensor. How many miles have you got? What's your MPG's been like lately?
Gas mileage is dropping a little, but not drasticly.

it's at about 147K right now.

I'll check those things tomorrow morning first thing.
 

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none none
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9,011 Posts
I had an old car, 86 Mercury Topaz, that had a bad fuel Pump, and would do something similar to what you described. Although nowadays, that kind of thing should give a CEL, and throw a error code.
A bad fuel pump will NOT throw a cell actually. Mine was getting bad enough that giving it gas even when at 1/4 tank it would sputter out at higher rpm and start bucking. Might also check the fuel filter and the front o2 sensor. The front o2 sensor can start failing but still read "in spec" and not throw a code. Could also be maf if equipped, or plugs, coilpack, or leads.
 

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2005 Impreza RS Wagon Auto
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3,683 Posts
If not the bad gas.. consider a broken ignition wire to one of your spark plugs.

Try filling it with premium gas.
I know premium actually gives my N/A worse performance and mileage, ignition related would most likley cause a CEL to pop up though but it is worth checking.
 

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2010 Forester 2.5X
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1,698 Posts
I know premium actually gives my N/A worse performance and mileage, ignition related would most likley cause a CEL to pop up though but it is worth checking.
Real Lyte.. love your picture.....it that your son?....get much sleep?

I wouldn't normally use premium, but If i thought I had water in tank.. that's what I'd put in.
 

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2005 Impreza RS Wagon Auto
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3,683 Posts
Real Lyte.. love your picture.....it that your son?....get much sleep?

I wouldn't normally use premium, but If i thought I had water in tank.. that's what I'd put in.
Haha I wish! That would truly be a spawn to be proud of...just an old school picture that went viral that I really enjoyed from maybe 10 years ago, lol.

Using any fuel injector clean usually has the water removing chemicals would probably be better than premium because I am pretty sure N/As are stock tuned to oct 89, hence probably why I saw a large decrease in performance (even though I have seen posts where it increased). If it was water, I wouldn't go to that gas station again regardless lol.
 

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The Modfather
2016 BRZ Limited - Manual 6 Speed Manual
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8,095 Posts
As a rule, I never get gas from a station where I see the refueling truck. It may be an unreasonable fear but I'm always worried about the new fuel stirring up crap and water at the bottom while I'm pumping gas in my car...
 

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2008 LL Bean (4EAT)
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4,909 Posts
I had an old car, 86 Mercury Topaz, that had a bad fuel Pump, and would do something similar to what you described. Although nowadays, that kind of thing should give a CEL, and throw a error code.
I wonder if it would give a CEL. The water in our gas did not. I don't think there is a sensor for bad gas or lack of gas.
 

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The Modfather
2016 BRZ Limited - Manual 6 Speed Manual
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8,095 Posts
you might get a cel because of the missing possibly.
 

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2008 LL Bean (4EAT)
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4,909 Posts
A bad fuel pump will NOT throw a cell actually. Mine was getting bad enough that giving it gas even when at 1/4 tank it would sputter out at higher rpm and start bucking. Might also check the fuel filter...
How many miles did your 2004 XT have?
How did you figure out it was the fuel pump and not the filter?
Or did you just have both replaced on suspicion and that happened to fix the problem?
 
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