When you changed the ecm did you disconnect the battery? If not disconnect the negative side of the battery and with it off check all the connections grounds, not only around the battery but the rest of the car. The tail light could have blown a fuse and with the tach and mpg acting up it sounds like a bad ground or a loose wire. Some wires look clean in reference to a ground but underneith there could be getting a bad contact. I do not think it is in the ecm as the lighting system runs on its own line
SPONSORED LINKS
Wednesday, September 23rd, 2009 AT 9:56 AM