My 2009 traverse got towed the other day. Picked it up and was driving home, and all of a sudden, it looses power, and will barley go 40 MPH. Does anyone know what could have caused this. When I got it back in February, my son pulled codes thru the OBD II port, and it showed to have a designated cylinder # 5 misfire. I changed all of the coil packs and plugged, using erideum plugs, and now all cylinders are reading misfire, and is showing to be running lean on bank 1 and 2 at the cats. Has anyone ever experienced this problem before. Any advice would help. Thanks.