Alright, I have a problem with my 03 Focus ZX3 2.0 Zetec car with 35,000 miles. Recently I have noticed while I am driving on the interstate that at certain points, mainly 50 to 65 miles per hour and sometimes at lower speeds, that if I try to go a steady speed but I drop down just a little and then speed up a little bit that I can feel the car try to slow down like it is downshifting and then it will jump up to normal speed again. It is not like the car is jurking in and out of gears or anything, but I can see it on the tach and feel a slight jump in speed. I don't know for sure if this is a transmission problem, or something else. I also have noticed that when I use cruise control on the interstate at the same speeds that it happens as well, also as I go down a slight hill the car will slow down and then speed up again as it does without cruise. One other thing is that I have noticed this start to happen more frequently after I cleaned my AEM cone filter. Could this cause my car to do this? I have heard that some oils used on these filters can cause problems with the intake. My car is out of warrenty, so I am hoping that it isn't anything too major. If it is the transmission, what would most likely cause this to happen? Or if it is something with the intake, what would it be? Any suggestions or help would be appreciated. Thanks.