There are lots of reasons why the paint may not have stuck initially. Incompatable paint, a thin layer of greese... it doesn't really matter now as you've gone to the metal.
I would go with at least 3 coats of primer.
make sure you clean with soap and water.
try to stick with the same type & brand of paint for all coats.
Check out other threads for techniques, i think a few months ago many of us wrote at detailed leangth.
As for the fuzzieness, what do you mean exactly?