I have a 2011 S60 T6 with 226,000K's on the clock.
In the last month replaced the Cat and the Oiltrap/PCV Valve (which was broken) trying to eliminate surging and stalling issue.

I have eliminated the surging with the new PCV valve.

Car still stalls when at idle. This is intermittent. Soemtimes its perfect. Seems to be worse when first starting cold.

Can anyone suggest any possible issuse?

Is there any possibility of vacuum leaks causing this?

How long does the ECU take to relearn after having the battery disconnected while fitting new PCV valve?

Would new spark-plugs help?

Any suggestions welcome ! Thanks

 

yes, vacuum leaks can create a poor idle as can weak spark. your plugs should be replaced every 60K miles/95Kms so you should be on your 3rd set by now. Coils going bad will generally result in a misfire CEL code but you may want to consider refreshing them as well. Generally any relearninig should happen within the first 300 miles or less. You may need to service the throttle mechanism or MAF sensor to make sure they are clean.

 

Further update, further head banging!
I replaced the spark plugs two days ago. The first 30 Kilometers it drove flawlessly. Now the stalling issue has returned with vengeance.
It is very cold here at the moment, it seems to be worse when its cold.
So far i have replace the CAT, replace the Oil Trap/PCV Valve and the spark plugs.
I cleaned the throttle body 6 months ago when the issue first started occurring
Is a MAF sensor issue like these symptoms?
Any comments welcomed...
Its one of those problems i just want to get to the bottom of!

 

Any further progress? When you put the new plugs in and it ran better, it leads me to believe its one of two things (Im am new to Volvo, but not new to motors), Spark, or fuel. You may have a dying/dead coil pack, or it could potentially be a stuck / clogged fuel injector. i would investigate these items if the problem is still relevant.