According to Europäische Stammtafeln, she may have been Gisela de Lorraine, daughter of Thierry II Duke of Lorraine & his second wife Gertrude de Flandre. The basis for this speculation is not known.
Albero Archbishop of Trier confirmed the donation to Kloster Wadegozingen made by "domina Gisela comitis Friderici de Sarbrucken vidua…cum filio suo Simone" by charter dated 1135. 1
Marriage Information:
Gisela married Gf. Friedrich VON SAARBRÜCKEN, son of Gf. Sigebert I IM SAARGAU. (Friedrich VON SAARBRÜCKEN was born in Saarbrücken, Rheinland and died before 1135.)
Sources
1 Foundation for Medieval Genealogy, Medlands: Friedrich [I].