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Sluggish Forester Revisited

Hi all,

I asked about a sluggish '01 Forester last month and tried the suggestions. I also had it into Subaru yesterday and got the plugs and wires changed. A misfire in one of the cylinders developed in the meantime (the car was rocking at stop lights). The work seems to have stopped that problem but the original remains. The biggest thing right now is the loss of power on the highway.

After I go about 30 km or so, the car will accelerate on its own and/or lose power only to catch after I've slowed about 5 or 10 kph. When I'm losing power, I can tap on the accelerator and get no response right away most times. The change in acceleration is enough to jerk me forward or back in the seat.

I tried the fuel system cleaner. I've also added basic fuel injector cleaner into the tank on every second fill. It seems to be better when the cleaner is in the fuel.

Any ideas? I'm going back to Subaru on Monday but their engine scan yesterday only picked up the misfiring cylinder.

TIA!

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Reply to
cloud dreamer
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Reply to
Edward Hayes

Yeah, except for the bit of sluggishness after starting, the surging doesn't start immediately - always on the far end of my trip (I travel

40 km on the highway to get into town). I also notice that the surging can continue for the rest of that trip but not always on the return trip (after the car has been turned off).

The fuel filter was changed 22,000 km (and 14 months) ago. Could that be the problem so soon after replacement? Faulty filter perhaps?

Or is a sticking injector possible? (I can also hear some rapid (valve?) tapping when I'm going uphill - not loud, but noticeable).

Thanks!

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Reply to
cloud dreamer

Didja check for O2 sensor function?

It can do all sort's of weird stuff if it is failing / has failed. Including the stuff you are describing.

It does NOT always throw a code when it goes bad (which is how I know all this stuff, driving around a while with it bad).

Reply to
Funkadyleik Spynwhanker

The tech mentioned that and probably got sidetracked by the misfired cylinder which did show up on the scan. I'll ask them to check it. Thanks.

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Reply to
cloud dreamer

I forgot, is this an auto-tranny? NMaybe a good power flush of the tranny will clean some gumminess outta some valve seats or something? Also, have you noticed ANY 'jerkiness' making sharp turns/maneuvering in parking lots?

Carl

Reply to
Carl 1 Lucky Texan

Yes, it's an auto. Wasn't sure if they still did power flushes. I had one done to my Golf years ago, and it made quite the difference. I haven't noticed any jerkiness making turns and that, but the sluggishness when I first start it can get a little jerky as it takes a second or two for the engine to respond to my foot on the pedal. Also, the shift between power loss and sudden acceleration on the highway can definitely be classified as jerky. (It's a wonder there isn't an imprint of my nose on the steering wheel :)

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Reply to
cloud dreamer

I suggest this COULD be a transmission problem. Many folks have had good results from multiple drain/refill drive/repeat - type sequences (3-5 times) or 'power flushes'.

Carl

Reply to
Carl 1 Lucky Texan

Good point. If you haven't had it flushed it's about time anyway.

Reply to
Funkadyleik Spynwhanker

I look to get it done on Monday.

My only other question is: if it's happens to be a failing oxygen sensor, what happens if it fails altogether? Will I find myself on the side of the highway testing out my new cell phone?

Thanks!

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Reply to
cloud dreamer

They usaully get 'lazy' first before failing completely. That's not to say a connectoer or wire isn't about to come loose. Plus, you would likely get some kind of diagnostic code indicating the O2 sensor after the CEL came on. I suspect the ECU would go into 'limp home' mode and default to the factory emergency map and you'd likely be able to at least drive to a safe place if not home or to a mechanic. Not sure.

Carl

Reply to
Carl 1 Lucky Texan

T'was the O2 sensor after all. They put in a new one today and so far it's riding perfectly.

Thanks all for the info!

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Reply to
cloud dreamer

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