Asking for a friend has an 06 6.0 just had new head gaskets and took truck out and tuck died on trip found loose ground from when truck was put back together truck back to running but computer was loaded with codes cleared codes now truck will die going down the road and start smoking and sputtering in reverse and also die took back to dealer they said it could be a ficm or bad harness any opinions? also found another ground that wasn't connected, truck is now out of warranty. Any help would be appreciated.

 

if they did the repair and you are finding that they did not complete the job, then take it back and tell them to finish the job. Tell them all the loose stuff and have them make it right.

 

If the job was done at a dealership, most warrantee their work for a period of time after the work is completed. I'd take it back as Senix stated.