I have an 03 s60 for a couple of days now the rpm gauge has been dropping down to around 500 then goes back up to around 900, yesterday I heading to my local hardware store when I came up to a red light I stepped on the brake to stop and my car stalls....I had this happen 1 other time when I was making a turn and lost power and almost hit the curb but was able to turn in time....now the cars starts right back up and have not have any other stalling issues but the rpm's just don't seem to be right, any ideas of what might be going on with the car??? should I change the gas and use a higher octane gas like 89 or 91??? not sure what to do at this point or what might be causing the rpm's to drop...any and all help appreciated!

 

Have the ETM, Electronic Throttle Module checked. It may need cleaning or software upgrade.

Good luck.