Legacy shuddering whilst accelerating

[Guest]

When the engine is cold, and i change into each gear (1st, 2nd, 3rd and 4th) and then accelerate the car shudders. This happens in all gears whilst accelerating. Would it be the clutch at all? or maybe the spark plug leads breaking down if they are carbon ones?

Once the car warms up it all goes away, thats why i thought maybe it was the clutch? any ideas or help would be appreciated.

cheers

[Guest]

sounds ,ore like misfire to me?

so plugs / leads (if fitted) and or coil tests would be a goos start

[Guest]

so best to take it to a mechanic and get them to check over the car? by the time i get there it will be warm so they wont be able to experience the shuddering etc.

[Guest]

you may have to leave it with them to cool down or leave it over night with them

It's just too difficult to diagnose this via the www sorry

[richm]

Hey Subleggtb,

As soon as I saw your post I reacted instantly. I have the same problem with mine and have had so for almost 2 years. Perfectly fine when warm, just hesitant when cold. The previous owner didn't mention a thing and nor did the professional check I paid for pick it up. So yes, I feel annoyed. For me the "shudder" isn't so bad, I can drive the car so that it is not noticable although I am still very conscious of it. I like things to be perfect and this is a constant black cloud to me.

So I am going to be watching this thread with much interest. I post up my problems here about 6 months ago and had a huge supply of many helpful suggestions - however none of which hadn't been tried before or helped the problem. I have taken mine to a number of Subaru experts who have had the car for several days - in fact a whole week so that each were able to drive the car when cold for several days. They changed / replaced everything they could - barr the entire engine - but are now still completely stumped.

So good luck. I hope for you it is something simple like the clutch or leads.

[Guest]

you sound just like me mate, i like things to be perfect as well although that is rather hard with any car. I just wanna get it sorted, taking it in to a subaru specialist next week for them to have a look at it so hopefully they can get to the bottom of the problem. From the suggestions and talking to other people it sounds like it may be the plugs/leads &./or distributor. I was thinking maybe the clutch also?? but who knows.lol.I shall keep you posted on what happens. Good luck with your car too mate.

[Guest]

I have same issue with my RSK when cold, it judders when accelerating. When warm after couple of mins it goes away, took it to subtech and they said it was O2 sensor and replaced but still does it!

[Guest]

 rs2 said:

I have same issue with my RSK when cold, it judders when accelerating. When warm after couple of mins it goes away, took it to subtech and they said it was O2 sensor and replaced but still does it!

Impossible to be O2 sensor fault when engine is cold !

O2 ignored during warm up phase

[richm]

Yeah, I had the "check enginge" light come on too about 18 months ago - the fault code was the oxygen sensor. So yes, it got replaced - also in the hope it would stop the cold enginge problem - but it didn't. Just as you say as well. It's interesting the "cold engine juddering while accelerating" problem isn't listed in the Dog and Lemon guide as a Legacy problem. Perhaps it should be? Interesting also that we both had the O2 issue...

With your RSK was the fault present when you obtained the car, did it creep up on you, or did it just suddenly appear?

[Guest]

O2 sensor is as important as spark plugs and has a service life

Poor running and shuddering are two different things

Poor running when cold CAN be fixed

[Guest Bjcnz]

Heya Guys, I have the same issue, but I'm fairly certain its my clutch (it needs to be replaced sometime soon anyways), in fact I know it is (pretty certain), because I had a similar issue with my last car (Impreza) however I was told it was fine, and later that week it crapped out on me, so had to leave it on the side of the road and surprise surprise, I come back the next day and all the windows are smashed in lol. If your clutch isn't biting until quite late, its probably it, and you can normally feel it slipping when it judders.

[Guest]

hahaha maybe you should just let your car warm up before you drive? it seems its just more than one person that is getting this problem? but to be fair i haven't experienced this in my 99 rsk.

will have a check tomorrow morning when i go to work and see if it shudders

[dubbedup]

i also have the shudder only when real cold, i know my clutch is on the way out tho so fingers crossed it is it.....

[Guest]

clutch shudder (unless its slipping) will only occur during operation (ie applying the clutch )

[Guest]

I get this too, When cold I get a shudder sometimes. Normally when turning. I assume this is the centre diff starting to binding.

Also when cold car jerks under load until it begins to make boost. I assumed that this was the Temp Switch which is under the intercooler in a water pipe. Normally this would read the water temp so the ecu and control fuel mix. And once the car makes boost the fuel mix must adjust via readings from another sensor?

Correct me if Im wrong here.

Oh I have a 2000 GTB Manual Wagon

[Guest]

ok mine doesn't shudder when its cold/

[Guest Bjcnz]

 Omegah said:

hahaha maybe you should just let your car warm up before you drive? it seems its just more than one person that is getting this problem? but to be fair i haven't experienced this in my 99 rsk.

will have a check tomorrow morning when i go to work and see if it shudders

lol you wouldn't have had to check, you would have known by now, its quite violent lol

[richm]

For me it's not the clutch or any part of the drivetrain. It is a type of misfire. Car starts beautifully, revs perfectly but it is as Smitty says "jerks under load until it makes boost".

Warming the car up when cold? Well yes, that is what Winger told me to do. And yes, that "sovles" the problem. "Just let the car idle for a few minutes before driving. It's not that bad." This attitude is the reason I don't use Winger anymore. Who wants to let their car idle every time they start it for 5 minutes wasting fuel? What Subaru enthusiast accepts their car to jerk while cold?

Interestingly and unexplainably the problem for me has gradually improved slightly over the last 18 months. It used to be even when the car had been sitting for half an hour and much more severe. Now it is only in the mornings and not too noticeable. Although ever present when cold.

Out of the list of items which have been replaced I don't remember the temp switch in the water pipe under the intercooler being done. Is it true as Smitty suggests? That this controls the fuel mix when the enginge is cold?

[Guest]

YES !

[Guest]

 Bjcnz said:

lol you wouldn't have had to check, you would have known by now, its quite violent lol

ah ok, nah mines fine hahaha

wouldn't you use more gas and wear the engine out by not letting it warm up before hitting boost? i thought boosting a cold turbo was a no no?

[Guest]

 Smitty said:

I get this too, When cold I get a shudder sometimes. Normally when turning. I assume this is the centre diff starting to binding.

Also when cold car jerks under load until it begins to make boost. I assumed that this was the Temp Switch which is under the intercooler in a water pipe. Normally this would read the water temp so the ecu and control fuel mix. And once the car makes boost the fuel mix must adjust via readings from another sensor?

Correct me if Im wrong here.

Oh I have a 2000 GTB Manual Wagon

Coolant temp is main base value for ecu fuel table calibration, yes other sensor have an input

Initial start is from coolant temp and crank/cam (early model with 6 tooth crank sprocket) or coolant and crank (with later 32? tooth sensor)

Many temp sensors (even new ones) are incorrectly calibrated ( I have seen as much as 15deg calibration error )

So that like car at frezzing or 0deg and the ecu thinks the engine is a 15 deg ! Woo hoo hard start and driveability issues BIG TIME

THIS FAULT IS FIXABLE !! but requires bypass units for ecu sensor wiring

[Guest]

Wingers changing the sensor for me on saturday, let you know if the situation improves.

[Guest]

Finally got round to having a look at my car, took it in the local subaru specialist in town and had a good talk with the mechanics and they suggested i try a product called Subaru Upper Engine Cleaner. So i bought the product (only $25.00) and went home and followed the instructions and squirted the product through one of the small vacuum pipes into the manifold. ALOT of smoke came out of the exhaust which was to be expected from all the carbon deposits from the combustion and intake systems (althought i thought i had blown the car up.lol) but the guys said that is normal as its cleaning it all out. Then took it for a drive to ensure everything was still performing good. The car feels more responsive and yesterday morning and this morning when the car was cold, driving to uni whilst cold there was absolutely no shuddering or anything whilst accelerating through the gears. Also it has improved and smoothed out the idle. So for me that was $25.00 well spent. Thought for some of you this may be worth trying. Cheers

[Guest]

 Omegah']

[quote name='Bjcnz said:

lol you wouldn't have had to check, you would have known by now, its quite violent lol

/quote]

ah ok, nah mines fine hahaha

wouldn't you use more gas and wear the engine out by not letting it warm up before hitting boost? i thought boosting a cold turbo was a no no?

1+ I was told (many many times) not to boost while cold, it wrecks the engine. Believe me I found out the hard way.

And I was going to suggest using the Subaru Upper Engine Cleaner as I had the same issue with mine before I bought it and pointed it out, I was able to get the price down by 800 bucks....I then bought the SUEC for $29.95. Did wonders I tell you.

[Guest]

does the UEC really work?