Foresters idles unevenly?

Aug 15, 2012 15 Replies

Driving my wife's 2002 Forester, I noticed today something I don't remember seeing before.



At idle, it oscillates (with a full period somwhere in the 1-2 min range): the engine goes from nice and quiet ~ 600 RPM to noticeably rougher, almost shaking, 1000 RPM. Weird. Wife tells that the car "breathes" and she considered it normal - so I don't know for how long it's been going on. Could easily be few thousands miles and over 6 months.



The driving part feel normal - no oscillations for no obvious reasons, reasonably smooth and does not feel underpowered.



Any guesses as to what it might be caused by, how bad it can possibly be for the car's health and what can be done to fix it (if fixing such a thing makes any sense)?



Thanks!



Dima


Oh, forgot to mention:

tthe car had seen dealer's maintanence service a few thousand miles ago, at about 90,000 mi, so the standard things that have just been replaced are:

Spark plugs, plug wires, fuel filter, air filter, PCV valve, water pump, timing belt. The hoses were supposed to be all inspected and replaced if needed. Don't see anyhthing visibly loose or cracked. The car does burn oil (about quart/1,000 mi) but there are no leaks anywhere after externally leaking head gasket has been replaced.

Dima

This may sound dumb, but could it be the AC cycling on and off? That might change the rpms and also cause some vibration.

you might try a throttlebody cleaning with the 'spray' type of Seafoam.

If it has AC and it is on, it not only MIGHT, it WILL.

Bingo! Boy, I feel pretty stupid... The really funny thing is that I DID think "well, looks like AC is coming on periodically" but the AC light was off and I couldn't feel any cold so I kept driving thinking that it wasn't AC.

Turn out that the little light no longer works and I did no pay attention that the AC dial was set to blow down.

Dima

Every time I would turn on the ac in my Subaru, the car would lose power. It's the only car that I've ever had that did that. This means that the power to weight ratio of this wagon was somewhat below acceptable. That's the breaks.

I had a '95 Ford Probe with 4 cylinder engine and 5 speed stick. Turning on the A/C was like throwing out an anchor.

David

A fan and an ice bucket would be more suitable for cars with motors like that.

hmmph...I have a 2000 Forester and the AC is on almost all the time in the summer. Granted, it's not a Porsche, but I don't really have any performance issues with it. It's a 4 speed auto too.

The car was an 84 GL wagon. I thought my engine was a dud but my boss got his wife a similar car that had the same problem. He never saw anything like it before. It was the worst of two worlds - poor gas mileage and poor performance. I tried a later model and it had a much zippier engine.

My Subaru had a 5 speed that was ill-suited for the engine. A big gap between 1st and 2nd with the rest of the ratios too close together. Mostly, I'd like to forget that car but a drive train that sucks to such a high degree just sticks to you. As an added bonus, one of the timing belts broke at 61,000 miles.

ooh, bummer. I had a '92 Loyale and also earlier models that made me want to get out and push. They just didn't have the zip that the "newer" models do.

"Loyale" gives me a chuckle. I would have sold that car out the first chance I got. I thought the sharp-crease boxy styling of these cars were cool but the engines seemed so balky and lazy that it turned me off to Subaru. OTOH, the new Subaru/Toyota seems kind of neat.

I like my 00 Forester, but that Loyale ('92) was a dog. One thing in its favor was its extremely tight turning circle...I could do U-turns practically anywhere!

regarding those tight turning circles...I was always replacing cv boots though. :-)

I think you're right about that. You would think that with such a wide engine, the turning radius would be just so-so. To be able to do a U-turn without stopping is always a good feature!

About the only thing special about the wagon I had was that 1st gear was so low that I could practically dump the clutch on starting with no slipping or stalling. My guess is that my clutch would have a pretty long life. The rear hatch had an awful problem with rust - I guess that was pretty special too. :-)

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