Hey guys please help been stuck for a week with this issue

[Rawze]

That is a pretty common issue with CM871's (a 2009 ISX engine) and also with Pete 386's.

A)> First and foremost, that ecm is notorious for this random shutdown issue as they age. You say you have replaced it 3 times but this still does not rule it out. Start the truck up and let it idle ... firmly the crap out of the top (straight down) and upper left area of the ECM casing but hard enough to dent the casing. Use the larger end a 1/2 inch extension bar or some other solid object that will reach the top areas ... and see if the engine cuts out while idling. If it does, then it is a known issue and therefore a bad ecm.
Here is a nice example of someone replacing ecm and still having this same issue ... : http://rawze.com/forums/showthread.php?t...0#pid12320

AND/OR its is almost always ...

B)> those 386's have a wire that goes to the batteries that is a small one. Maybe a 30 amp fuse or something .. at the battery terminals. That fuse and wire likes to short out causing the ecm to randomly die. here is some info on why they do this...
ref: http://rawze.com/forums/showthread.php?t...05#pid3505