Can anyone assist me ? I have an 02 s80 that has developed a hesitation or slight surge during ecceleration at 40 and 60 miles per hour. I have replaced the fuel filter ( the old one was very dirty, I captured the fuel and it was black) I have also put Sea Foam in the tank and driven 200 miles with no change in symptons. I checked the fuel after installing the new fuel filter and it is clean. I have less than 5000 miles on the spark plugs and no check engine light. the car has 206000 miles on it and it is a non turbo engine. I would appreciate any input in helping me solve this issue.