Hopefully someone can help me. my 03 s60 is acting strange. when i put the throttle to the floor and it stays at a lower rpm (kicking down into passing gear for example but still @ low rpm) the car will take off great and feel awsome, then i can feel that strong power go away and then come back, and it keeps doing this back and forth about every 2 seconds. when its @ a high rpm i dont notice it and it feels awsome. it feels like the turbo is spooling then getting restricted somehow then spools good again and so on. the other day i heard a really fast clicking under the hood and found the source. it was the "vacuum solenoid valve". ( it has a bunch of vaccume lines going to it). i know it doesnt make that noise all the time. i have no check engine lights or anything coming on. is this the source of the problem or could it be caused by something else. Does the vacuum solenoid valve control the turbo?? any suggesttions would be greatly appreciated.

 

Yes that controls the Turbo Boost.
Does the Check engine light flash at all when it happens?

 

No, i have no check engine light coming on. could a vacuum leak be causing this?

 

A vacuum leak is more unlikely. Sounds like a similar issue to what I had. My car surged under boost, as you described. It was the boost control solenoid, mounted to the side of the air cleaner box. Mine was a 30670448 and was about $50.00. It's simple to install, but you just have to be certain you match the hoses up the same as the old ones..

- Lynn

 

It does have the symptoms of a sticking turbo control valve. I'd pick on up and see if that remedies your problem.