Vanguy1991G20

Hi everyone, hoping someone may have had this issue before. Driving on the highway at higher speeds under load going up a hill this has happened twice now. I could start to smell Electrcial burning, felt under the seat and ECM was super hot. Shortly after That van died At high speed and got if off to the side of the road. Engine would not restart, no blown fuses and no error codes and had to get towed to a shop. The shop I took it out ended up saying it was a bad injector which they replaced but it would barely run (ran super rough wouldn’t idle properly) we ended up changing out the ECM as well and problem solved? Drove home very cautiously. 2 years later same situation, highway driving, high speed van dies. Would not restart, checked all fuses, none blown , no error codes This time I could smell the ECM again and decided to try swapping it before calling a tow truck . I managed to get a new ECM. swapped it out van ran normal and Managed to get home. At this point I have driven it for short trips around town with no issues but suspect I have something with a bad ground that may be frying the ECM?? Any help guidance would be greatly appreciated as I would like to be able to count on this unit knowing I have solved the issue . Thanks in advance