Chrysler Repair: random misfire, crank sensor, fly wheel

Question
QUESTION: Hi, I have a 97 sebring lxi it drives fine till i hit the highway, at 100 to 120km the check engine light comes on and it flashes every once in a while. I had it checked and they got code P300 (random misfire) the cylinders keep changing on every test. I have changed everything that
can be changed. wires, plugs, dist..., map sen.., egr valve,all 4 O2 sensors, crank sensor, ECM, had the injectors flushed and tested, i even tried using premium gas. and every time they clear the code it comes back when I hit the highway, any help will be much appreciated



ANSWER: time to look inside the engine then burnt valves or burnt pistons.

---------- FOLLOW-UP ----------

QUESTION: The problem started when i changed the engine. It cant be engine related because it was changed the first time and i was loosing compression along with the misfire code, and it was changed again because of the compression problem. After changing the engine the P300 code came back different engines same problem. My mechanic is miffed his last opinion was cracked fly wheel.

Answer
did u get a reman  engine or a junk yard one? The fly wheel the same or different one. I think u need to take it toa dealer and have them look at the misfire monitors  and see what ones are missing because your tech does not have a cluse to to really figure this out based on what u have replaced thus far <wires, plugs, dist..., map sen.., egr valve,all 4 O2 sensors, crank sensor, ECM, injectors flushed and tested>
all of that work is hack work and guessing crap. Take it to some one who knows what they are doing.