Maddy Mry

How's it going? I am in serious need of some assistance . A friend of mine has a 2003 Tahoe 2wd 5.3l v8. It is going into reduced engine mode almost immediately after starting of vehicle and a short distance of driving (1 or 2 blocks at most) then shuts off. Then won't start for quite sometime. When stopped it has a rough idle and sometimes when shifting gears it dies.it has a brand new alternator and battery. Prior to this you would be driving and the all dash lights would come on and the doors would cycle through lock unlock lock randomly. A Chevy mechanic was told us that that BCM looked like it was going out. Would that cause all this or what should I look into? Don't have money to take it to shop but my friend has kids and is in a bind without her vehicle. Let me know. Thanks

BigSam13

Check/repair the ground strap at the rear of the engine. If fact, check all of the grounds. Had the exact same thing happen on my 03 Suburban.