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What is the model number of your furnace? it on the furnace rating tag
Ok, I can't give you model specific info with knowing what model you have. What you describe sounds like a flame sensing problem.
I can't tell you that because I don't have the model number. What I can tell you is that most of the flame sensors look similar to the one in the attached pic. It's positioned in the burner flame. You can try cleaning off the metal rod with steel wool or an aggressive scotch brite pad. Many times that's all that's needed. Turn the power off to the furnace before you try cleaning it.
Some older models don't have a separate flame sensor. The ignitor is the flame sensor and these can become problematic as they age. The fix is to install a kit that adds a flame sensor. Your friends theory is not credible. If the draft fan (the blower has nothing to do with the burner staying lit) wasn't working right the burner wouldn't fire up at all.
Ok, that doesn't change anything I've said so far.
That's not likely to fix this. If you have the type that uses the ignitor to sense the flame you need to add a flame sensor. If you have a flame sensor you need to clean it
Ok, if it's that old it's likely that it's one of the units that uses the ignitor as the flame sensor. This was a bad idea and every model since has a separate flame sensor. The flame sensing issue gets worse with age. The fix is to install the retrofit kit that was developed to overcome this design flaw. You're lucky it lasted this long. I've diagnosed your problem and gave you the solution. I'd appreciate a favorable rating.