Volvo Repair: Shaking muffler?, volvo wagon, rubber pieces

Question
I have a 1900 Volvo Wagon 240. Recently I noticed that my muffler was loose. I know that the rubber pieces that keep it up are ripped, and those will be replaced shortly. However, I think there's something else wrong. After my muffler came loose, my car started shaking while stopped. I'm having trouble accelerating as well and get bursts of speed at random moments. Any idea what else might be loose or what I can do?

Answer
I assume its a 1990 and not a 1900:)Possibly have broken engine mounts or transmission mount. As for the sudden bursts of speed...You should start by having the fault codes read. Did you possibly hit something? Maybe bend the exhaust?If the exhaust is restricted it could produce the symptoms you detail