Engine Surging

[surfbeast]

sounds like a plug wire loose or some type of computer problem. Especially since you changed the fuel filter. I was having a simular problem but the car would just shut off, sometimes it would buck and the trany go into neutral even while in drive. I battled this for months and finally found a frayed ground wire. Most mechs hate this kind of problem cause it isn't a constant thing. You'll most likely have to eliminate one thing at a time.

Good luck!