I'd check the balancer as Mr. Yuck suggests just to be sure. I had a jeep that separated the balancer and could never time it correctly except by ear. If I used the numbers then it ran like a turd and if I went back and checked it 2 hours later it would be slightly different. Then one day I shut it and my ears hear an old school telephone ring coming from under the hood???? The balancer had come completely loose and the outer rim of the balancer would continue to turn on the inner ring after the motor was shut off (making the ringing noise). Finally all those symptoms made sense.