What Quadgop said. If you’re ending up with a clump of stuck-together fettuccine within an otherwise unstuck bunch-o-noodles, it definitely sounds like lack of stirring may be the culprit.
Not to ask the obvious but are you getting the water to a rolling boil before you put the pasta in? Pasta that heats with sub-boiling water tends to be nasty and sticky.
Use more water, some salt and make it a rolling boil. Overcooking will cause the pasta to get gummy, so lean towards ‘al dente’, leaving the pasta slightly firm.
Old Schoolers believe olive oil, say a tbl spoon, will keep it from sticking, but I feel this helps upon straining it, not while it is in the pot.
We cook with big lobster-pot-sized pots, even for 2-4 servings. Also, noodles are going to stick regardless of cooking technique after they are strained/drained. At this point, you need some type of sauce or gravy (red sauce with meat can be called gravy).
The sauce can be good ol’ butter, or oil and garlic, a marinara, meat sauce, or even al fredo sauce, etc. Left alone, even the best pasta will stick to itself.
I always add a little olive oil to the water before I put the pasta in. I don’t know if that’s the reason, but I make pretty good pasta. Well, it doesn’t stick together at least.
Another thing I would add, is to add the pasta slowly into the water, about one serving at a time to keep the water boiling. I accidently put the whole package (1 lb) in at once the other night, and had sticky pasta galore.