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2000 Subaru Forrester Kicking/Losing Power


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helpymysubaru
New User

Dec 14, 2009, 11:18 AM

Post #1 of 6 (2904 views)
2000 Subaru Forrester Kicking/Losing Power Sign In

Our Subaru used to have a problem where--only when we filled up from near empty--we'd run into problems where the car would violently kick and slow down. Often, giving it more gas would help but the other day the car basically lost power to the point it wasn't moving. We stopped for a second before going on and the problem was fixed. Has happened ~2 times in last two months. Occasionally will do the kicking part (but not the slowing down) on the highway in cruise.

Went to mechanic, computer read no problems. However, mechanic (who we trust and isn't looking for $$$) noticed the wires were original factory issue. Got the wires & spark plugs changed, along with an oil change. Car worked great, went to gas station. Filled up on gas, problem started happening again. Problem will not stop now to the point the car cannot be used. Mechanic also mentioned fuel filter probably needs changing (can't tell without removing it and labor would cost just as much as getting a new one...).

No lights are on or have been in last month. Check engine light was on about 1.5 months ago but turned off when we got to Autozone and car has no history of the light. Discovered at AZ we were low on oil, assumed that was the problem then as we weren't having any use issues.

Fast forward to today, car towed to mechanic as problem made it impossible to drive. Mechanic looked car over and drove with issue, check engine light on. Code said that all four cylinders were misfiring (while the car was moving). Obviously, impossible. Mechanic didn't think the fuel filter was at fault and so didn't change it.

Car worked fine 'magically'--even according to the mechanic. Told us to take it to the dealership and let them know what the issue is as they've never seen anything like it.

So please...help! WE're supposed to take a long trip this weekend but this is obviously causing a few kinks.

2000 Subaru Forrester, no idea of engine size, 141K.


Sidom
Veteran / Moderator
Sidom profile image

Dec 14, 2009, 2:23 PM

Post #2 of 6 (2900 views)
Re: 2000 Subaru Forrester Kicking/Losing Power Sign In

It would probably be best to follow the advise of your mechanic. This definitely sounds like a close to impossible problem to solve over the internet. Also it's going to take the right equipment to find.

If I had to guess I would say a cam or crank sensor is intermittently breaking down but at this point we don't even know what is missing, to cause the problem so that is a totally blind guess.

They're going to have to hook a scope up to as many circuits as they can, run the car and see what is breaking down when the problem occurs..........


Loren Champlain Sr
Veteran / Moderator
Loren Champlain Sr profile image

Dec 14, 2009, 6:15 PM

Post #3 of 6 (2895 views)
Re: 2000 Subaru Forrester Kicking/Losing Power Sign In

>>Code said that all four cylinders were misfiring (while the car was moving). Obviously, impossible.<< That would be P0300 (Random cylinder misfire). Not impossible. That means that something is affecting all four cylinders. Too rich, too lean, cam timing, ect. Hats off to the 'mechanic' to admit it is above his knowledge. There is nothing wrong with not knowing the answer. It sounds like you have an honest mechanic, and I'd stick with him in the future.
Loren
SW Washington

(This post was edited by Loren Champlain Sr on Dec 14, 2009, 6:17 PM)


helpymysubaru
New User

Dec 15, 2009, 12:39 PM

Post #4 of 6 (2889 views)
Re: 2000 Subaru Forrester Kicking/Losing Power Sign In

Well, we're still at a loss. Subaru will only read the computer (which doesn't say anything is wrong) and won't test any of their possible theories unless car is doing the problem.

Follow up thoughts?


Sidom
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Sidom profile image

Dec 15, 2009, 9:55 PM

Post #5 of 6 (2885 views)
Re: 2000 Subaru Forrester Kicking/Losing Power Sign In

That's the tough thing about intermittents. Unless it's acting up, it's almost impossible to find. Some systems, like fuel or ign there are some readings you can go off of that will help lead you in the right direction.

But with electrical, such as a sensor or injector, you really need your scope hooked up and catch it while it's failing to know for sure. Resistance reading are useless. The bad part will ohm out fine but only breakdown when hot & under load, and that's assuming it's a bad part, there is also the wiring harness & connectors that could be causing the problem.


Footnote: I just reread your original post. After what you said, I would probably current ramp the fuel pump. That is a reading that could show a possible problem even when the vehicle is running fine. If the amps are too low & the pattern is distorted with uneven humps that would be a sign of a failing fuel pump but to be honest you really don't see a lot of Japanesse pumps go bad.


(This post was edited by Sidom on Dec 15, 2009, 10:02 PM)


helpymysubaru
New User

Feb 4, 2010, 7:45 AM

Post #6 of 6 (2863 views)
Re: 2000 Subaru Forrester Kicking/Losing Power Sign In

New update, Feb: Changed fuel filter in December as Subaru dealership wouldn't look at it without a light on to diagnose.

Car worked fine for two 600+ mile trips and most of January commuting. Started shaking issue again, this time with less powering down. Will do it on highway and only a hard shot of gas will help. However, the check engine light has been on all week (except the time we took it to the mechanic *facepalm*).

Got the code read at Autozone, says it's either fuel injector, 02 sensor or the like. Mechanic won't work off that as he says AZ doesn't have a good enough sensor.

Car's at a new mechanic now but I'm wondering: any thoughts to the issue? I'm thinking maybe the old misfire code was correct and that that's the cause of the violent shaking?






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