i have a 1990 d150 5.2 automatic 2 wheel drive when driving it will stop running then a second later it resumes its like someone tunred the power off then on again some days it will do it the next day it wont although it is happening more frequent. thought was fuel pump at first mechanic did fuel pressure check was good put new filter on and new lines going on to the fuel filter. new fuekl relay. no codes are showing doesnt seem to have the same power as before. Mechanic states he checked crank sensor and all relays. i went and got him today and he drove with me in it and it finally did it before he couldnt make it to this. in a 4 mile stretch it cut out then resumed power He states possible ECM. what else could it be men thank you in advance

 

could be a bad wire/connection. i know when i got my 81 the wire that fed the fusible links had a bad connection and would sometimes cut out.