I took my 1998 S70 t-5 the the Volvo dealer last week for repairs. My wife said the car when she tried to accelerate was just bogging down and would not go anywhere. It did this just a few times. The car has 72,000 miles on it so we were going to take it to the dealer to get the timing belt changed anyway. The service department said the 60,000 mile service would fix the problem. I went to pick it up and 3 miles later the check engine light was on. My wife took the car back to the dealer they said the light was coming on because when they cleaned the injectors and the fuel rails carbon got on one of the sensors (I should have taken it myself). That same day the check engine light came on again and the car started emmiting black smoke, when idling and under acceleration. I called the dealer they said it was still because of the extensive (ha ha) fuel system cleaning they had done and it would just take a couple of days for all the carbon to blow out. I have had fuel systems cleaned before and never seen anything like this. Has anyone else had this problem? The car seems to be down on power also. We have never had a problem with the vehicle until Volvo got a hold of it. Please Help!!!!!

Thanks