I drive a 2001 Escape, 2.0 liter, 4 cylinder, 5 speed, standard. A while back it started to drive bad. When I shift through the gears, if I don't rev it to 3000 rpms, it stumbles badly. From a dead stop in first gear I have to over-rev to get it rolling, or else it will stall. This stumbling occurs in all gears when I accelerate. Once I reach cruising speed in 5th gear it appears to run fine. It idles very smooth and there are no "check engine" codes displayed when I use my OBD-2 code reader. I have tried a few things based on what I have read in this forum, but still have the problem. Any suggestions? Any help is appreciated.