engine management light is on and the coil light flashing while driving

I've never heard of a "coil" light. If that is the Check Engine light, flashing indicates the most serious of the over 2,000 conditions that can be detected. It means too much unburned fuel is going into the exhaust system where it will burn in the catalytic converter and overheat it. You're supposed to stop the engine right away to avoid that very expensive damage.

The place to start is by having the diagnostic fault codes read and recorded. Those will indicate the circuit or system that needs further diagnosis or the unacceptable operating condition. The people at many auto parts stores will do that for you for free.