Back-fire or "lean pops"

My van will start and run for about five to ten minutes, then it will start chugging, pop a couple of times (back-fire or "lean pops"? Not sure) stay running like that for ten to forty five seconds and then die.


The computer showed EGR valve and they replaced that and it ran without any problems for three or four weeks then one day it started doing the chugging thing just like before. Took it to shop, they said a vacuum line was bad. They fixed it and again, good for few weeks then boom. This time it showed MAP sensor was bad, replaced it then again same as before. I had the plugs, wires, ignition pack? I think its called (plug wires connect to it) changed. Crankshaft sensor, fuel pressure regulator and a sensor on throttle body, all tested. I changed out ECM? (The computer) and intake manifold gasket was replaced and most recently I had to replace alternator. It lasted only a week after the manifold gasket repair and it is doing it again. I hope someone has heard of this and can help show me what will fix the real problem. Oh one last thing. I noticed three or four of the wires that go to the MAP Sensor or the plug next to it had about a quarter of an inch of wire exposed where the insulation had somehow came off. I taped each wire with electrical tape temporarily and it has not made any difference. Thank you for your help.