The past few months with my '01 S60 2.4T (139K miles) have basically been a nightmare. So I had my battery replaced less than a year ago, my alternator replaced 2-3 months ago, and spark plugs and ignition coils replaced a month ago. I also had my mass air flow sensor "cleaned" but not replaced because they wanted to try that first.

However, this morning when I started my car, I got the "El. Power System Service Required" message for about 5 seconds, and then it disappeared. I also get the service light but that disappears when I start driving. Whenever I'm driving, and idling at a light for a little while, the engine (maybe?) is quiet until all of the sudden, it rumbles and churns really loudly and then goes back to being quiet. It also doesn't accelerate as smoothly as it used it. It feels like it shakes/vibrates some.

Any ideas of what could be going on? Could it be that mass air flow sensor or something else?

Thanks!

 

I've got a similar problem with my '02 S60 w/ 133,000 miles on it, although mine doesn't sound nearly as bad. Mine is simply a rough / frequent misfire at idle. I don't notice any power loss or rough acceleration. In the last 4 months or so I've replaced:

Spark Plugs
PCV system
Battery
Alternator
Timing Belt / pulleys
Air filter

None of that made a bit of difference.

I don't get a service light, so I can't pull a code. I'm starting to suspect the throttle body as it's a common issue, but from what I understand, my car doesn't fall into the group of vehicles with throttle body problems, so I don't know.

I'm definitely going to keep my eye on this thread though.