Got ready to change fuel filter and when I pulled the fuse, that fuseholder is discolored as if from excessive heat. I bought glass fuses that were supposed to be a relacement(Autozone), but when I put one in, it lasted about 3 miles. I put back in a replacement that is the original type, and it works fine(so far).
Why would the fuseholder have gotten that hot at some time?

Should I check for excessive current draw?

Where can I get the original style fuses?

BTW, haven't completed fuel filter yet because I can't get the banjo bolts loose. Where do you disconnect the lines to take the whole assembly off the car?

A lot of questions, but thanks in advance for your help.