My car was doing that last week a little bit then it ended up not even starting up at all. It ended up being my fuel pump which is pretty strange seeing as I only have 8400 miles on my car.
check all vaccum hoses for cuts/rips as well as tight connections. then go to the IAC valve. after that my next guess would have been fuel filter, but you just replaced it....
LOL, yeah, I just replaced mine like 2 weeks ago and the one I took off looked brand new. There must be a flaw in the design or something cause it seems that alot of people on here have the same problem alot!