Rough idle and low oil pressure below 2k RPM


New Member
I've got a new lambda probe that you can have. It's the bank 2 probe, 4 wires, located under the car.
It was from eBay and did not cost me much so its yours if you need it
Thanks for the offering, but I live in another country so shipping would be troublesome. As the 2nd lambda mainly insures that the cat works as it should, replacing it would probably lead to replacing the cat as well..... o_O


New Member
Good to hear that the battery helped things. The line above has got me thinking - with regard to non-original ignition bits, does this include the coil?

The reason I ask is that with our AUA when we had the recurrent misfire issue, I had already fitted new plugs and leads (Bosch), newly refurbished injectors and so on (which all helped a bit) but the problem persisted with engine-wide misfire counts racking up and then going to 3 and then 2 cylinders after ECU-mandated shutdowns - and eventually found that our original coil had casing and insulation cracks due to age. Was able to get a non-original coil off Amazon overnight which would get the car running in time for my other half's commute, so I went with that. Arrived Sunday morning, fitted, and car started and ran without any hesitation for the first time ever, all cylinders better than ever before. After about 5 minutes of idling smoothly and warming up, cylinder 1 suddenly shut down - the cheap coil had failed on that circuit - but it had proved that the compromised coil insulation was the problem as the other 3 cylinders were running smoothly. Sent it back for a refund, and ordered a Bosch that was delivered 3-4 days later and it worked properly first time and is doing so still.

Wondering if the non-original coil has something intermittent on that output?

Added - just read the last few posts as well - definitely replace the caps, the pair (fuel and oil cap) should cost less than 12 quid all in delivered overnight. I also replaced the coolant lid on all 3 cars for the same reason (although that isn't your problem today).
Had another look on the coil and it looks to be unoriginal. Would be almost tragicomical if such a simple thing caused the issue. Will try to source another one 👍 Found my original lying around in the boot, but one of the connectors is sadly broken off, or else I would have tried it.


New Member
Is it me, or does it sound unbelievably noisy tappet-wise? When you went back into the car you could still clearly here it. I assume these have hydraulic lifters?

I'd certainly want to compare it to a well running car with same engine if by chance you know of one.

Not much point going further with electrical / fuel related issues if the basic mechanicals aren't right. If, say, you have hydraulic valve lifters that have clogged / stuck / failed you'll have all sorts of potential issues as a result of retarded valve timing and incorrect lift.

It might just be your phone / camera being very sensitive, in which case I'll get my coat, but I'd be interested to see how your car compares in engine noise levels to a known sweet example. These do suffer from piston slap at higher miles, but this sounds more tappety to me and you seem to have biblical compression. I reckon your engine thinks it's a diesel, hence the confused running :p

Good luck with it: there's nothing worse than doing careful diagnostics, coming up with a good theory, buying the parts, carefully fitting them (and finding the old part indeed looked a bit dodgy) only to find the problem remains.

Hopefully you'll have a breakthrough and all of your previous work will pay off in terms of a particularly nice car with long term reliability built in.
Yes if it were a mechanical issue it's useless to throw money on it by buying lots of expensive sensors. Should have just bought a replacement engine at the start and swapped it. I actually think at this point that swapping the engine would be less tedious than lying on the ground replacing all these miscellaneous sensors 🤕 I've look for replacement units but they are scarce in my area/country....


As mentioned already it sounds like tappets from watching your video, I'm no mechanic but it sounds just like my old focus that had the same issue, a garage sorted it with no further issues but it was tappets. Sorry I can't be of any further help but I do hope you solve the problem.


New Member
Got ahold of a original coil with part number "032 905 106B" nearby. That didn't help either.... 🙃 I have been troubleshooting for 2 months now with no success. With this idle issue and the low oil pressure warning - I'm kicking the bucket and getting rid of it. Thanks for all the input! Will hopefully find another A2 with better service history 😊

Sporadic low oil pressure warning:
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A2OC Donor
Was looking for an old 'low oil pressure' thread and spotted a thread on rough idle issues -
And another on random low oil pressure warnings -
If some of the symptoms match it's another reason to call it a day

Cheers Spike

Quite a few cars are prone to this. Back in my TR days, the Triumph TR6 was notorious for it.

Reason for mentioning this was the giveaway symptom was the idle would dip as you pressed on the clutch. What was happening was the crank (now floating as it had lost its lateral bearings, what with being in the sump and all) was being pushed out of line by the clutch action, effectively bending all six conrods sideways.

I'm not sufficiently familiar with the AUA's clutch arrangements to know if the clutch operates via slave and lever or another method, but I wonder if the revs drop or engine noise changes when clutch is pressed?

Anyway, listening back to the videos again (original plus one I posted) I'd certainly understand if you went for another engine or another car. Odd it has such massive compression though.