just installed an engine and it started fine. ran but not good so i moved the distributor and adjusted the throttle body. i then saw two connectors on the firewall by the computer connection so i swapped them. the car ran better but the speedometer did not work s. the battery also was dead the next morning so i swapped them back. the speedometer started working but the battery still died. i jumped it off and heard aclicking noise under the hood by the intake manifold. it is a 1995 mustang gt with a stock 5.0 engine out of same year car with explorer intake. the engine has 80000 miles on it.