fuel fouled plugs

i just rebuilt the motor in an 85 crx si. it has been bored .020 over and is complete with all new parts. when i first cranked it after the rebuild, the vacuum line going to the t.b. from the map sensor was undone and this caused the plugs to foul out. when i reconnected it the car ran perfect. the guy who owned the car had it for almost a week somehow it started to foul them out again. the vacuum lines are all connected and everything else is in tact. no e.c.u codes. it happened over night. im thinking that some kind of component went out or something. any ideas? also is there a way to disconnect that control box on the drivers fender well? would that have something to do with my problem? thanks in advance