rough idling on on 4g54 2.6L

rev drops and settles back normally

like when I'm on reverse tachometer reads close to 900 rpm then backing up it goes down to 5-700 rpm
engine sometimes dies on me

this happens sometimes even on drive when I'm crawling in traffic or slowly coming to a stop

When on neutral idling subtely drops from 900 to 870 and goes back to 900 rpm

this has been happening on and off but disappears when i put in new contact point but comes back again after a month or 2