I recently purchased a 2001 silhouette. It was over heating when I purchased it, fixed that problem (missing a head bolt). Hooked it up to a code reader and there was an O2 sensor code. I have replaced the O2, and now there are 2 new codes one for the MAF sensor and the other is the evaporative control purge valve. I have replaced both things and the codes are still coming up. Suddenly it haas lost power to the MAF sensor plugs as well. Can anyone help?