Are there any symptoms that predict sids?

Sometimes. Prematurity, observed apnea (stopped breathing), sleeping face down, cosleeping are all associated with sids. Long qt syndrome can be diagnosed by ecg, it usually runs in families, and can lead to sudden death.
Not reliably. Here is a new study reflecting the modern thinking on SIDS deaths... http://www. Medicinenet. Com/script/main/art. Asp? Articlekey=185460.