uneven idle v6 4 motion

[crypticx]

For as long as I have owned this car it has always had an uneven idle. About a month a go my friendly vw mechanic told me i needed 2 new O2 sensors,- the car seemed to be running ok at the time so i thought i'd leave it and do some research.
From what i could discover 8 times out of 10 it was dirty contacts or they just needed to be cleaned or some other sensor was faulty, so it went into the too hard basket.
Then as I was setting off for Sydney about a week ago I noticed the engine was starting to idle roughly and as the week progressed it just got worse - I should have replaced those sensors,
This morning i discoverd a vacuum leak in the evap canister line which is hard plastic and has a corrugated section to allow it to bend - right where the corrugations start it was split , with any luck this is probably the reason the computer claimed the O2 sensors faulty. having to deal with unmetered air.
This engine has so many vacuum lines and sensors it's scary and i think i was extremely lucky to find it, I could have spent Thousands and been no better off. This time it was a piece of duct tape
So there is a moral to the story CHECK YOUR VACUUM LINES FOR LEAKS


Cheers
David

[Back Door Shenanigans.]

Hmm. You got a picture of this? Mines having the same exact problems, Bad idle, reported oxygen sensor gone....

[Rybky]

What is the exact error you get from the O2 Sensor?

I have similar problems, idle is sometimes rough and the B1 S2 O2 sensor reports "slow to respond". I replaced the vacuum hose too as mine was split at that flexi section too, didn't make much difference. Need to get around to replacing that sensor at some point.

Adam

[crypticx]

spot the difference -
[IMG][/IMG]
[IMG][/IMG]
i found it by hearing a slight whistle and then by feel
I reset the computer to remove all the learned values and now the car has much better acceleration and better fuel economy.
the 2 o2 sensors identified as faulty - which were not - were the ones before the cat

[gringo_54_oval]

my bora v6 runs crap that hose been replaced MAF sensor been replaced and 1 of the o2 sensors been replaced but the thing is it runs rough only when its been pushed a bit i dont want to keep pouring money into this car if its never ends.
*its idle is rough when its cold
*once its warm (90 degs) soon as it gets to 2700rpm theres a surge in power its like iv put my foot down flat when i havnt
and if you push it some the EPC lights comes on for 1 minute then turns off but the ESP light stays on until you it off and it all resets itself.
*While the EPC ESP lights are on in idle it just stalls

would anyone have an idea??
i dont wanna go to toyota direction

[Manaz]

my bora v6 runs crap that hose been replaced MAF sensor been replaced and 1 of the o2 sensors been replaced but the thing is it runs rough only when its been pushed a bit i dont want to keep pouring money into this car if its never ends.
*its idle is rough when its cold
*once its warm (90 degs) soon as it gets to 2700rpm theres a surge in power its like iv put my foot down flat when i havnt
and if you push it some the EPC lights comes on for 1 minute then turns off but the ESP light stays on until you it off and it all resets itself.
*While the EPC ESP lights are on in idle it just stalls

would anyone have an idea??
i dont wanna go to toyota direction

Get the car to a specialist (one with VAG-COM or another VW-specific diagnostic tool) for a start. There's too many things it could be to give you a definitive answer over the internet.

[Back Door Shenanigans.]

Sorry to rebring up this thread but is that pipe the one on the drivers side coming from where the fuel lines come out and going into a black container (Activated charcoal container) near the radiator fluid container?

[Jmac]

Yep always cracks
Jmac

[crypticx]

No it's the one running from the charcoal container to the inlet manifold which because the engine is sucking unmetered air makes it run so rough

[Back Door Shenanigans.]

Isnt the corragated one the one that runs from the fuel tank into the charcoal container (red). I.e the breather hose? (Yellow) The hose that runs to the intake manifold is solid and not plastic. (blue)

[crypticx]

It's the blue tube the corrugation are where the tube makes a right hand turn to go behind the inlet manifold and transfers from chassis to engine
Maybe your's has already been replaced with a non oriiginal. it dosen't matter I replaced mine with some good quality flexible rubber fuel line.

[Back Door Shenanigans.]

Ill have a look tommorow thanks though. Just trying to find out if theres anything else that is causing a problem because at the moment mines idling like a drag car which isn't so good.

[graeme86]

Another common vac leak is down near the fuel pressure regulator.
Look at engine manifold on right (passenger) side where the flap mechanism is. You will see the fuel pressure regulator on the fuel rail near there. There is a rubber T- piece in the vacuum line coming off there that can get cracks in it.