I acquired a 2005 S80 when my my passed. I realized if you try and give the motor more gas in order

[Edgar G Bowman]

to pull out quickly it kicks and bucks, and is definitely not taking the fuel. If you bring the car up to speed in a very controlled throttle, it will get to 70 MPH with little problem. If you get behind a slower driver and you give it gas to pass, it does the same thing. I notice a small vacuum looking part that has gotten hot and brittle, and the top does not stay on. Could this part be causing the problem. My Mom had a lead foot, so I know the problem has occurred since I took possession. It almost reacts very similar to experiences I have had when water has gotten into the fuel. Just to be sure that was not the problem I put gas dryer in, and have now burned several tanks of gas. Any suggestions where I should start? Thank you for your help!