My car motor recently started shaking and i have no power on each shift,??it was fine before i change the power steering pump and got an oil change on it..why might this be happening ?

See if you knocked a spark plug wire off or crossed 2 wires. Maybe burned or cut.

check that your accessory belt is on correctly, if so then open top of s pump if you have foam then s pump not bled properly . if still a problem then replace the pump.

In my case, the 4 bolts on the drveshaft were missing. Once new ones were intalled, car runs like a champ. They might be loose too. I would chrck that.