running lean at idle?

[turbobooster]

ok heres a before observation about a month ago i had a exhaust , vacuum , and oil leak and at that time my OTC monitor would bounce from lean to rich and then go into cloosed loop after a decent warm up at idle ... ok now a month later all leaks fixed i hook up the OTC monitor and it stays in lean only ( it doesnt bounce back and forth to rich like before) and it doesnt go into cloosed loop even after letting it idle for a while, why is it running only lean now? is this good or bad? also y wont it go into cloosed loop after engine temp reaches its point?