Ella15

I have a 1995 Jeep Cherokee 4.0l straight 6 that has been running rough for a while. It all started with what I thought was bad gas, the idle was extremely rough. All of that was flushed out of the system since. I have also replaced fuel filter, pump, injectors (upgrade to bosch quads), rail, cleaned throttle body, new IAC valve, TPS sensor, battery, plus wires and cap and rotor, and had 2 "mechanics" work on it. It idles better but once it warms up it violently shakes and feels like its misfiring (not a death wobble, not suspension related). I am exhausted and out of ideas, the mechanics couldn't fix it, though they charged like they did. Still tossing code 27. From everything I'm reading my next option is replacing the crank position sensor. I don't even know if I'm on the right track anymore, but I know I love my Jeep and I'm asking for this forums help please. Please Help save Ella.