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.

 

It could be the same problem I am having. I had taken my 97 Volvo 960 to get the diagnostic read and it said it was the "Camshaft Position Sensor". I'm still trying to find the the blame thing is on my car. Mine, ever now and then, does a momentary hesitation at acceleration and this is probably my cause. If your "check engine" light is on, you may want to get it read with the computer.

 

My engine light was not on for the first two weeks of having these symptoms, the light did eventually come on and it turned out to be a bad coil pack.