Thank you for your responses.
The other engine problem involves the Lionel T&P F7 ABA where the lead engine has forgotten its ID. The F7B Bass unit seems to have remembered its ID. I haven't seen sparking from rollers on these engines. I have reprogrammed the A unit but haven't yet retried them as a train. I'll do that this afternoon.
How old are the F7s? If memory serve me correctly about a year ago Lionel had an issue with engines remembering their ID. Folks returned them for repair. It might be the same issue.