Stall on idle in traffic - missing at low RPM

I never experienced either a stall or missing in all the time I have owned this MY01 V70XC 2.4T3 AWD. Engine has always had fully synthetic oil/filter/air filter changes at 7500miles/12 months. Transmission has had multiple Gibbons flushes. Sparking plugs changed at 50k miles. PCV done 5 years ago.
I obtained the following DTC's using Vida/Dice.
CEM door unlock signal too hogh Left Rear.
CEM bc48 transponder faulty signal.
ECM 3503 missing
ECM 3533 missing cylinder 3
ECM 3543 missing cylinder 4

I shut the engine down and once cold I removed the coil packs (marked Bosch Germany - Volvo) and sparking plugs: Volvo R6. The plugs did not look fouled but were due for a change. The loom area was dry and with expected brittle fragments of slit sheathing. Every coil pack showed cracking, three had a very small crack, the other two bigger cracks.

Today I cleared the fault codes fitted the new Volvo R6 plugs (028thou) and coil packs to their original positions. The engine is not starting though it turns over normally. I only tried twice as I have 5 new Bosch coil packs on the way from Volvo.
Any advice on how to proceed is welcome. Nick

Just an additional thought: it is nagging me in the back of my mind that this is in part fuel related. Here our fuel octane ratings seem way higher than the US. Standard is 97 and we have Shell V Power (Super Unleaded) 99 BUT just recently the standard petrol has at least 10% bio ethanol. I blame this for engine troubles, so even though Super Unleaded is 153.9 p per litre as apposed to 144.9 for regular I have reverted to 99 with no ethanol so a full tank is well over £100!

Well - I would start with the basics: fuel, compression, spark, timing.

How's your fuel pressure?

MAF condition?

Loose intake pipe or hose?

Vacuum leak?

All those change the air and fuel ratio - and stumbling at idle suggests the fuel/air ratio is off...

Your story isn't clear. Did it gradually start to run poorly, and then one day, it finally said no more and stalled and then has never started again?

Or did it suddenly stall out with no warning and has never started since then?

If it was a sudden stall, when was your timing belt last done? I might worry about a failed belt.

Brett

Any cracks in the coil pack can weaken the spark (short to ground thru engine head).

Also, you said the coil pack harness had cracks in the sheathing. Examine this harness carefully for any copper corrosion. The coil-packs draw pretty high current, and any resistance can weaken or undermine the spark.

Thanks to each and all. On re-reading today I realise it's a confused picture I have given. Truth is despite everything the car is probably in better condition than me - I had a health scare in March and it's been impossible to get medical help until three weeks ago, since then I feel I've been on a nightmare ride where I am sent to hospital for this and that scan and told to arrive for day surgery (endoscope and biopsy) without any explanation, clear or otherwise of what "they" suspect is wrong -last Tuesday I was told my condition is not curable and it's palliative care only folks, but hey we don't have the histology report yet, so stop asking questions and wait. ... Sorry to get embarrassingly personal on here everyone..

So having realised I didn't properly re-install the cold air charge pipe at the intercooler end, I re-did the DSTC codes and just had the two misfires on 3 and 4. - per Vida/DiCE. The car has not been moved, indeed it has not been restarted in 10 days. I did the timing belt 40k miles ago

So today armed with new sparking plugs and coil packs (Volvo) I cleared all codes. ETM checks out and "readiness" is ok so is the ignition immobiliser state. The engine turns over but seemingly not firing and no attempt to start.Have not yet checked fuel pressure (fuel tank is just over half = 36 litres. All coils are brand new Volvo OEM so are sparking plugs. The engine dies at a traffic light stop at a junction near home (in D) the when started the next day at home the misfire occurred - shut down and not re-started.
I am wondering if a continuity check of the spark plug harness, wire by wire would be worthwhile or should I just get a new harness from Volvo and slice it in - there is a good walk through somewhere on the web of this and I have downloaded it to my Mack.
Am I missing some bl*** obvious point? Any help much appreciated. I have not got a fuel pressure gauge and didn't want to undo the fuel rail Schrader valve while charging the battery. Car is in car park as I now live in a block of apartments.

If the car doesn't start, ignore the misfire codes on 2 cylinders. It will start and run with 2 dead cylinders. Those misfires are not preventing the car from starting. Back to basics as Astro14 already advised. Fuel is an easy place to start. Turn the key to the on position without trying to start. Do you hear the fuel pump run? If no, you've got a problem with the fuel pump or the circuit providing power to the fuel pump. If yes, now is probably a good time to hook up a fuel pressure tester and make sure the pump is delivering the proper fuel pressure.

Brett

Wait, wait, palliative care only? My goodness! That’s a tough thing to hear. I wish you the very best. I’m no closer to helping with your car, but sure wish I could help with that diagnosis.

Thanks everyone for the good whishes honestly. When you get to 73 years young (February) you become surprisingly philosophical. There is nothing like hearing about your own mortality to wake you up and make you realise what really matters. I just want to say in passing how wonderful this forum is, that's because each and every one of you is fair and decent, out to benefit the "community" of Volvo owners and enthusiasts. I have experienced many forum sites but this is the best by far. Members dont snipe they don't judge they just try to pass on their hard learnt knowledge. I am sure everyone benefits. For that I cannot thank everyone enough!

But the purpose of loging in now is to update my misfire no-start situation. So I changed out all the Bosh (Volvo) Coil packs for new, changed out the sparking plugs for new Volvo and checked out the fuel tank pump/fuel rail pressure. The injectors were my main suspects (originals on an engine that has always had fully synthetic 0 - 30 engine oil (Shell Helix) and Super Unleaded 98 RON fuel in most of its 180,000 miles. So, last Tuesday (first day after Christmas the Post Office opened for business I sent all 5 fuel injectors off to a specialist gasoleen/diesel fuel injector cleaning company: www.injectortune.co.uk/ Today I received them back. The company charged UK £78.00 inculing return postage for, ultra sonic cleaning of 5 injectors. They also engraved each one with their numeration (I had used nail varnish) they ran a static flow test before and after and they replaced all the 'o' rings and internal filters. They tested the cleaned and reassembled units for resistance, leak test and spray pattern. They threw in a free carabena style keyring fob for good measure ( no mountain climing with it). If the weather forcast is a fair as suggested I will be refitting the fuel rail in the morning. This has saved me so much money, - my tame Volvo parts supplier (in South Wales, FRF Volvo, Swansea) want north of £80 each for new Bosh/Volvo injectors. By the way Volvo charges £18.00 in the UK for a complete set of Injector 'o' rings.

Sorry folks web site is not allowing me to post jpeg attachments for some reason.

Hey Nick - Thanks for the update. I will stick to cars this post...but I am thinking of you and hope things are going well...

When the wife's Volvo XC had about 240,000 miles on it, I had the injectors rebuilt and flow matched.

Despite the use of the best (top tier in the US, good detergent) fuel and frequent use of good cleaners, the injectors were a mess. 15% flow difference across the set, poor spray patterns, everything.

After the rebuild/match they worked like a dream. Idle smoothed out. Power was better. Like a new car.

I wish that I had done it far sooner.

Incidentally, the car has a fresh set of plugs, but has 4 original coils out of 5. They seem to be working perfectly.