I'm new here so this might have been brought up before.....anyway today my 2004 S60 2.5t was running fine when I left my drive way. After 2 turns the car seemed to loose power and began to ilde rough and the check engine light started flashing. Anyone know what the problem could be.
I love this car and have not had much trouble until recently.

 

Mine just did that and it turned out to be a fouled plug. If you can get the code red, it will tell you exactly what it is. If it is a plug or coil, it will tell you exactly which cylinder.

 

Since I posted this my problem has been solved. I first changed all the plugs....no help. Then my neighbor, who's a mechanic, got the read for me and it said "misfire in 2 and 4. What we did was switched 1&2 and 4&5 coils and the we got a "misfire in 1&2 reading. So he unplugged 1 and there was no change. He continued to unplug 2-5 and everytime there was a change in the idle. So I just replaced the 1 Ingition coil and everythings good.

 

I had the same problem and replaced the one bad coil. It fixed it for about 2k miles and now it is happening again so I am replacing the other 4 coils and would recommend changing all of them for anyone with a misfiring issue. Change all plugs and coils at the same time if you have the $$$.

 

IMHO, coils don't go bad all at once so replacing all 5 when one is bad is unecessary. Plugs are due to be replaced at 60K miles and unless you are consuming oil or have a fuel mixture problem, just stick to OEM plugs and check the gap when installing new (don't assume they came from the factory gapped for your model). If you have coil issues across multiple plugs, I'd closely look at the wiring harness and its connectors. Also note that weak spark is only one cause of a misfire CEL. When the FPR went on my S40, I got a P0303 (misfire #3) regularly until I replaced the FPR