Ford Ranger / B-Series :: 1995 - Mystery Stall Every 1 To 3 Months

For the last 2 years 1995 ranger 2.3 will run great but every 1-3 months will just stall. Will than try to start it for a couple of minutes and in 1-8 minutes will start back up again as if nothing was wrong and then be fine for another week, month, 2 months etc. It has never happened at first start up in the morning but at times will stall 2 minutes after start (at traffic light of course). At times will turn off to run into store, come outside, no start, try for couple of minutes and then starts up fine. Changed out fuel pump, etc, etc. Biggest problem is no codes and, of course, when mechanic looks at it nothing is wrong.