New to this forum and glad it's here. I purchased a 2002 S60 Volvo (non-turbo) 4 mths. ago (139,000 kilometers). After owning it about a month, I'd occasionally get this message upon start-up..."shift up or slow down" and the engine would chug and run with a rough idle. After this happening occasionally for a couple of months, I brought the car to our Volvo dealer and they replaced the Ambient Pressure Sensor as they said their computer diagnosis showed it to be faulty. That was yesterday. This morning, in very cold weather, the car idled rough at start-up again but showed no message. From my previous occurences, I observed that shutting the engine off and re-starting it would eliminate this problem. The engine runs perfectly smooth on all other occasions and I really do enjoy driving this vehicle. I'm a bit concerned though that I could be constantly throwing money that I really can't afford on this vehicle to try and rectify my "sometimes" problem. Anybody else ever experience similar and if so, what did you find was the problem ? This vehicle was maintained by the dealer since new and I'm it's second owner. Any help or suggestions would be greatly appreciated.

P.S. - I've run only 94 octane gasoline since this problem first started.

 

I would try cleaning the throttle body now and see if that fixes it.

 

Is cleaning the throttle body something that my husband could do ? He's fairly mechanically inclined and has always insisted on doing our own oil changes and things of that nature. He's very fussy about these things being done often. Where is it (throttle body) located and what is involved ? Should I tell him I have another job for him or is this something that only a dealer should do ? Also....what type of cost would I be looking at if the dealer does it ? Many thanks for your advice. :-)

 

The throttle body is on the side of the motor on the Non-turbo motor. He should be able to handle it. He can follow the hose from the air filter housing to the motor. Where the hose attaches to the motor that is the throttle body. He can use some brake cleaner on a rag and wipe it out good to clean it.