Mobil-1 is bad for our engines. The facts are there. Just start reading them. It has nothing to do with opinion.
My 1990 Ford F-150 would do the same thing with the oil light...... It was low oil.
When you ask questions over the internet, we aren't able to diagnose your problem to a tee, so you are going to get some comments about needing a new engine.
Sounds like you already got a new engine. SOA warranty? Maybe you should just take it back to the same dealer that noticed the issue and advised you to fix it by buying a new part that didn't actually fix your problem.