stalls and high idle

my 89 4.0 will stall at idle , sometimes, and it is not often ,but if I run it hard the idle will be high, sometimes ,this is a random thing do not know when it will happen ,runs great at speeds Im thinking it is electrical I have a new gas filter and pump ,when I go to start it back up it feels like the engine is out of sync.and lopes then starts . any suggestions

The Renix is notorious for the idleing problems and the list is so vast on what you can check that I think people are going to tell you to search Renix Idle issues or something similiar. I have almost the same problems as you and have been chasing these little idle gremlins for awhile. All I can say is do the search it will help out immensly. I know thats not much help as your reading this but wait till you see how many topics there are.