1998 Ford Escort rev and idle issues

I have a 1998 escort zx2 it has less than 30k miles on a factory rebuilt engine and has been well maintained its entire life. Sometimes it idles down extremely slowly from 3k to 2k rmp and when it gets under 2k it dies completely and the only way to get it to idle decent is to mash the gas all the way to the floor and let off. Plus sometimes on cruising speeds above 55mph it will not idle down at all when you push the clutch in it stays at that rmp even if you completely stop. Also when accelerating in any gear it has what can be best described as repetitive hesitations, like instant loss or gain of significant power but is not in any way misfiring. Sort of feels like the ac is cycling on and off very fast but its not. Most of the time it does the same thing when decelerating in all gears. I have checked for vacuum leaks and replaced the pcv valve, maf, iac, acts, tps, speed sensor and bcm, plus a complete tune up and fuel pressure is within specs. I am not getting any codes and timing is dead on. I am stumped. Please help