problem
 

sometimes when im drivin all of a sudden the car will start to shake, if i push on the gas it does it more. i never know when it is gonna happen. What i do is downshift one gear and the car runs fine. i think its something related to fuel getting to the engine. im gonna replace the fuel filter. any ideas? thanks

i think you are on the right track with the fuel system. also check the ignition. one of the plug wires might come loose, and when downshifting will make contact again and the engine runs fine

im thinkin a few things now:
Change fuel filter, check plugs and wires, check fuel lines, check for a vacuum leak.