I have a 96 Sentra 1.6L GA16DE (201,000 miles). Yesterday my car was running normally and when I went to drive it after it sat a couple hours a very loud grinding noise occurred when I would try to accelerate from a stop. As soon as I pushed more than a 1/4 way down on the gas pedal the grinding noise began and when I was in neutral wasn’t present. I let the car sit a couple more hours and it ran completely fine and drove normally after. Today engine is misfiring and running on only 1 cylinder so I did an oil change and reset the ignition timing. Now car runs normal again. Clueless as to what I should do at this point. Distributor was replaced with new one a year ago and last week I replaced the cap and rotor.