My car was doing the same thing, I replaced my O2 sensors and it went away... Might want to clean your throttle body too, I have heard a dirty TB will cause the same problems.
~*TJ*~ 97 GL Sport Zetec MTX
~*RIP*~ Connie~*1/21/02*
Sold the Zetec, now the prouud owner of an 01 VW GTi VR6 - Sold the GTI now have 97 Mustang Cobra