well i would get (if you have the money) a brand new radiator or you can get a second hand one from a wreckers and take it to your radiator shop and get them to check it for holes, leaks, cracks etc and get it flushed cause no doubt it could be blocked
2 things may have caused this
a blocked radiator
or exhaust gasses in your water... hence the requirement for a block check ( you will want to find out if you have a bhg before you do damage to the engine... saves you alot in the long run)
that sucks bout the afm lol
it's probly just full of crud and stuff so when you blew it out it fixed it right up... dirty connectors... a few things... but i would suspect this won't happen again
could be just old brittle wires... but if she's running sweet as now i'd say it's fine
good luck
