Can my muffler make my car run slower and shake?

CLOGGED FUEL FILTER OR WEAK FUEL PUMP CAUSE CAR TO HAVE LACK OF POWER AND SURGE.CHANGE FUEL FILTER,CLEAN FUEL INJECTORS WITH CAN SEAFOAM BY ADDING TO 3/4 TO FULL TANK OF GAS.CHECK FUEL PRESSURE SHOULD BE 41 - 47 PSI FOR 2.0L OR 3.1L ENGINES AND 9 - 13 PSI 2.2L TBI INJECTION SYSTEM.IF FUEL PRESSURE GOOD CHECK TRANSMISSION FLUID LEVEL.FAULTY TORQUE CONVERTER WILL CAUSE LACK OF POWER AND ENGINE SURGE.A STOPPED UP MUFFLER OR CATALYTIC CONVERTER WILL TAKE SLOW CAR DOWN MAKE IT SPEED UP SLOW DOWN SPEED UP SLOW DOWN.

Yes it could if there is blockage in your muffler. the shaking is because of the back pressure in your exhaust feeding into the engine instead of exiting the engine. this build up of exhaust gases can cause backfires and damage to other vital engine parts such as valves,spark plugs ect...