Idle issue (bouncing idle)

Hi everyone, I have an audi a3 8p 1.6 with the BGU engine code. I have posted about this before but I cant find the original post.

The issue itself is that the car at times has a bouncing idle, in the past it has stalled out (total 4 times this has happened on different occasions). I have a few videos so I will get them uploaded on some vid to url site on what it does to give you a better idea. So far I have cleaned the throttle body, map sensor, replaced my rad fan assembly (due to it not working). In terms of codes I remember something to do with a lean bank 1 code at some point but I cleared it and haven't seen it again. I have also had another code that said something like idle higher than expected intermittent air something but i can't exactly remember. I have heard this is due to the block breather which is the thing under the engine oil cap, I have no idea how to replace this but I have found the part for £15 and I would appreciate if I could get some feedback on what I should do. I did remove the oil cap while car is on and its easy to take off and revs don't change at all. I have got the common symptoms for it I guess (unstable idle, oil seeming to disappear although the car is parked up and a lot of water out the exhaust). I am unsure what this means.

If any more details are needed I am happy to provide them and videos. I am trying to get the car sold by the weekend as someone wants it for then and I want give them a good car which doesn't have any issues.

https://streamable.com/9k1mtx here is a video of what the car does when I try hold it at an rpm.
https://streamable.com/1swrvk upto 10 second mark is what it does on its own then I am revving as when I rev it past 2k for a bit the issue disappears and the car acts normal again.
I got my cousin to drive the car and he says it seems to be lacking power too.

Have bought a part called engine block breather on eBay https://www.ebay.co.uk/itm/183740530701 for next day delivery.
I’ve taken off the hoses on the old one but I can’t figure out how it comes off, been scouring the internet and can’t find anything on it. I’ve been pulling trying to twist at it all sorts but it won’t budge.
Here is some photos of it and inside.

RobinA3 said:

All your symptoms points to an air leak post MAF.

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I thought that too but I’ve had a quick look and can’t see nothing, I’ve also not been hearing nothing either (I started it up and listened for leaks in the engine bay). This doesn’t have a MAF only a MAP. The valve thing I ordered should be here today so hopefully I can get the old one out, it is quite dirty which is what I expected on a 15 year old car (looks like the same sludge inside it which has been appearing in my engine oil cap, mayoish colour).

Something I forgot to mention, sometimes the car idles and drives fine while other times it’s awful. Maybe sitting in a auction yard does this to a car especially when it’s this old. At the moment it’s parked and only driven on the odd occasion up and down my road to keep the brakes from giving me issues.

RobinA3 said:

A trick you can do is idle the engine and spray some carb cleaner around any pipes and joints before the throttle body, if you here a change in engine tone then that suggests an air leak in that area as the engine will pull in the carb cleaner.

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That’s a good idea. I was gonna get it smoke tested but to be honest I couldn’t be bothered to get it insured. I will try that later on today.

RobinA3 said:

If you take a picture of your engine bay we can point out what parts are etc.

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Any idea on that PCV equivalent that I’ve ordered? Should be here tomorrow but I still can’t get it off on mine.