04 endeavor .I have a misfire cylinder #3. changed injector, coil twice, spark plug well seals,. it only has misfire problem 50% of time, runs fine the rest of time. it can misfire cold , hot, idle, accelerating , and seems to be a little worse with a/c on. anyone think its a pcm? cost 400.00 , so kind of hesitant to replace it. thanks for any advice

 

what is the compression in that cylinder ???