Thank you all for your input on this issue. Being my brother’s bike I did not spend enough time understanding what his shifting problem was. I asked to take the bike and my first encounter was that the rear derailleur was shifting lousy. I also noticed the derailleur jockey wheels were worn. I went ahead and replaced the jockey wheels and put in a new shift cable. After I had the rear derailleur shifting nicely is when I discovered the fraying of the front derailleur cable. After replacing the cable and getting the shifting working well (on the bike stand) is when I took a test ride and discovered the problem with front derailleur shifting under load. I mentioned this forum to my brother during the weekend and explained to him the problem I was having and he then told me that he had been having this problem recently. I of course did not know about this previous to my post and assumed the “having problems shifting” as nothing too concerning.

What’s occurring is this: the bike is a triple chain ring and when riding on the lowest and middle chain ring in front everything is fine. When I shift to the largest front chain ring the shift happens without issue but when I begin to pedal the chain makes lots of noise and ultimately wants to fall back to the middle front chain ring. The noise continues until I shift to the middle chain ring. I will again have some time this week to work on the bike. I will then do a better analysis of the situation. I understand the bike is old but my intent is to fix if possible. Since this is my first experience with this issue the advice is invaluable.