95 Legacy Wagon with strange vibration/juddering

[urabus1995]

Hi Guys. I have been doin a search on here, and am starting to get a bit worried about my symptoms.

Occasionaly, over the last few weeks. my legacy has started behaving badly. It normally happens about 5 mins of driving. It starts to vibrate/judder quite badly, and seems to lose throttle response. If I change down from 5th to 4th, I can keep up road speed, and after a minute or so of this vibration, it clears and I can proceed as normal.

The first time this happened, I thought it was a bad road surface, it felt like I was driving on large stones, or ridges in the road.I stopped after a minute of this, and inspected all the tyres and brakes, thinking maybe something was binding. The car ran fine for several days, with no sign of vibration at all. Then one day last week , I had the same thing occur. Again it cleared in about a minute.Ran fine for another few days.

Yesterday the same thing happened. It lasted longer this time.

Its almost as if its misfiring, with the lack of power that that would cause.

It idles fine, it starts first turn, and once this vibration stops, it runs as normal. From what I have read here, on my searches, it could be several things , Drive train, sensors, brakes ?? I am suspecting an electrical fault of some sort, but when I stop to check it out, the problem goes away.

It is a manual shift, 2.0 litre Japanese import wagon, with about 85,000 miles on it. It has always run like a dream just as you would expect from a Subaru at this mileage. It is however, a 1995 car , I got it at only 25000 miles in 2004-5 if I remember! Is there something that might be affected by age rather than milage which could cause this problem.

It ran without hassle this morning. Hope for some genius solution from you guys, you normally come up with the right ideas?

John (Scotland)

[davebugs]

This is often a brake caliper hanging up. Add that to the list of non-engine things to check out. Infact I'd put it at the top of the list if the engine is sounding fine and no CEL.

[urabus1995]

I had all my brakes renewed last year, at least the rotors and pads, not calipers.That was my first thought when this started to happen, but yesterday a couple of mins after it occurred, I had arrived at my destination. I felt each wheel hub and rotors, they were all cold. I would have thought a caliper problem would have created lots of heat and smell?

That certainly was the case with my wife's Shogun when its caliper seized. It was HOT!!

The thing I find strangest about it is that It goes away without me doing anything. This the kind of problem I hate. Would a misfire , an injector or a faulty sensor somewhere cause the juddering? It is quite alarming when it happens but as I say , it quickly stops and everything seems normal.I hope its not the transmission beginning to fail.

 

ps. there is no CEL, and the engine is as quiet and smooth as the day I got it( except at 5000+revs when it just sounds beautifully growly

Edited March 30, 2009 by urabus1995
forgot to say

[Gloyale]

cv axle

[urabus1995]

cv axle

 

Really, do you think that could be the cause?. Why would the problem come and go like it does? Its gone perfectly for the last two days. not even a hint of vibration at all speeds.

I recently had drive shaft boot replaced, the usual suspect, the one beside the CAT. Thats the 3rd I have had on there!!

Maybe the axle has had enough of running out of grease?

I will check further . Thanks again for your suggestions. Does no-one think this might be Electrical in nature?

John