we have a 2000 S40 w/about 65k mi and just after we bought it the turbo line started to leak ( which i understand is a common prob) and shortly after the o-ring was changed it started to run like crap.... better when it was cold out, worse when warm . i changed the plugs , air and fuel filters with only moderate improvement. took it to local dealer and they read codes and it came up w/(and i quote from bill) ECM 44- needs spark plugs & oil change--aftermarket plugs in car needs 60k service and valve est 608.00. when i inquired about this valve they gave me the name (which has since slipped my mind) and we looked in the VADIS detail to find it > It is in the cylinder head page and is called the exhaust solenoid by the parts listing . from all i can see it appears ,by the VADIS exploded veiw to be on the front of the head but there is no other info about it and the mech@ the dealer stonewalled me on its location etc.... i smell one of those "the book calls it 608.00 but it really only takes about an hour things". can you shed any light on this? i know that the part,even if i buy it from the dealer is only about 85.00 . I currently own a 750il and do all my own work including engine and electronics myself so tearing this thing down won't be a big challege but it is my wife's car and i would rather NOT start on this till i am sure of exactly where it's located and what else i am going to need... i want my face to remain on the ront of my head ...lol thanks a lot talk to you soon brian duffy
we have a 2000 S40 w/about 65k mi and just after we bought it the turbo line started to leak ( which i understand is a common prob) and shortly after the o-ring was changed it started to run like crap.... better when it was cold out, worse when warm . took it to local dealer and they read codes and it came up w/(and i quote from bill) ECM 44- needs spark plugs & oil change--aftermarket plugs in car needs 60k service and valve est 608.00. when i inquired about this valve they gave me the name (which has since slipped my mind) and we looked in the VADIS detail to find it > It is in the cylinder head page and is called the exhaust solenoid by the parts listing . from all i can see it appears ,by the VADIS exploded veiw to be on the front of the head but there is no other info about it and the mech@ the dealer stonewalled me on its location etc.... i smell one of those "the book calls it 608.00 but it really only takes about an hour things". can you shed any light on this? i know that the part,even if i buy it from the dealer is only about 85.00 . I currently own a 750il and do all my own work including engine and electronics myself so tearing this thing down won't be a big challege but it is my wife's car and i would rather NOT start on this till i am sure of exactly where it's located and what else i am going to need... i want my face to remain on the ront of my head ...lol thanks a lot talk to you soon brian duffy

 

Did it mount on the top of the valve cover?
Maybe the VVT valve?
Also have you checked the coils for cracks? does the symptom happen more after the car has been driven for a little while?