Last night the bulb that lights the upper portion of my tach was out...by the time I got home it was lit back up again. Anyone have any insight or do you guys just think the bulb is loose?

Also, when data logging in the vehicle, I will lose communication and not be able to reconnect until pushing on the wires going into the ECM. What are the common wires between the ALDL and ECM that I should check for loose pins?

Vehicle is an 87 camaro, any help is appreciated.