I changed the fuel filter 2 month ago, and the car was in repair, i only played with the fuel pump to try to fix the gas gage, but there was wires that were needed to be weld dont know if that did something to it. It dosen't work still
when you turn the key to run does the pump power up? There is a lead right by the alternator (white wire with male connector I believe) hanging out of the plastic shielding. That is a fuel pump lead, connect 12V and the pump should run.
So you got power to the pump, that's good. While the engine is running listen to the pump for a couple minutes, kneel down behind the bumper. It sould be steady no variation in pitch. If you hear any the pump could be bad or as you said faulty connections. A fuel pressure gauge would be much easier, you can mount one on the fuel rail or better yet get an extension from caspers and tape the gauge to the winshield. When the car bogs watch the pressure.
You bet, lots of things can cause those issues. I think some of the more common causes are the MAF or the coil but thats assuming you've taken care of the basic tune up stuff.