check all ur filters for clogging, after that... like kidcarbuff said...after check ur brake/clutch fluid levels, how does the pedal feel, too stiff, too soft, engaging low, engaging high...if the clutch is feeling iffy and everything else is ok, then it's probably your clutch, it could be ur fuel filter, and depending on ur mileage it's time to replace that, check the spark plug wires for cracks or corrosion, change ur spark plugs....there are several things u can do .... it's just a matter of paying attn to your car so that after you do each step...you can see if the problem is solved...

hope this helped