What else could be wrong after replacing O2 sensors in my Mazda protege 5?

[Eddie Van Lance]

After 100K Ck engine light came on, hooked up scanner, replaced both O2 sensors, check engine light went off, and still runs really bad, 1st & 2nd gear can barely get moving without stalling & jerking after 3rdgear, runs good and smooth. In rev. car get plenty of fuel and backs up great. Help!