I purchased a 99 trans amautomatic w/o an engine trans or engine wiring harness. I then purchased a 98 trans am LS1 with a 6 speed a wiring harness already installed on it. When i put the engine and trans in and went to plug everything in, i had a problem. On the inside of the car(pass side firewall) where you plug the engine harness into the interior harness, the 98 engine harness had 3 plugs on it while the 99 harness only had 2 plugs. There fore there is one extra plug from the engine harness that is not plugged in. So i put the 98 6 spd computer in it and the car starts and runs great but i have no gauges and the interior lights stay on constantly. So i then tried the 99 automatic computer and with it all the gauges work but the car simply turns ober and does not fire the plugs to start it. Why is this? Can anyone offfer any suggestions on what i should do?? thanks