2001 forester shudder while idling

I have a 2001 Forester automatic trans. It has started shuddering intermittently when it idles, almost like a rocking forward and back. It also has a rough time getting moving coming out of stop lights, and this is also intermittent. My check engine light hasn't come on. Does anybody have an idea what might be the cause of this?

Reply to
jfriedman
Loading thread data ...

I have the same problem in my Impreza. Has been this way for a while. Although the problem is intermittent, it only shows up when the engine is cold. Invariably, it disappears when engine temp reaches its steady point. Also, I noticed that the problem (hesitation and in worst cases shudder) occurs more frequently in wet weather.

A friend told me it's likely to be a bad/corroded contact to an oxygen sensor. I am waiting for the thing to become more reproducible before bringing the car to mechanic.

DK

Reply to
DK

If I had to bet, i would suspect torque-converter "stalling"..I.E. Failure....

Reply to
Roger Buttsnort

The "wet weather" correlation suggests ignition. O2 is possible, I suppose.

In the dark, with a spray bottle, you can mist over teh engine as it runs. If you see arcing, replace plug wires and maybe the coil pack.

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

Correct. If insulation is beginning to fail, that'll cause you to see arcing inthe presence of aerosol moisture.

Not necessarily. These aren't binary devices. They can be leaky and still mostly work before they entirely poop out.

I ran into a subaru tech in a social context and he said a lot of his day is mired in plug wires and coil packs to correct driveability issues.

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.