As LTG says, sounds like you have some wear to the flipper / plunger mechs which cause drag and weakens flippers, ball launch, etc. Relatively easy to repair/rebuild, and will give you tremendous satisfaction.
A great starting point for DIY repair is Clay Harrell's This Old Pinball DVD's. i think they are less than 10 bucks each. He has 2 dvd's that pertain to modern games (1991 and up). Spending an hour watching will help you learn a ton. I have found them to be much better than most videos on youtube.