Missing and backfiring just off idle. Air box?

[JMitchell]

I have an 84 Carrera. It has run perfect since I purchased the car 10 years ago. The other day after driving the car for an hour I turned the car off and after a few minutes went to restart. Usually it starts right up once I just hit the starter. I hit the starter but not long enough and it did not start. Not sure if I heard a back fire or not. Then as I turned the starter over again it started right up but then when advancing the throttle just past idle it would back fire and spit and cough. Turned the car off and tried again but still the same symptom. Called the wife to bring a rope and come get me. After towing the car home which took about an hour in total time I started the car and it idled and accelerated fine.

Could this have been and air box issue. I have heard about the air box issue after a backfire but thought it was with the CIS and not the motronic system. Would the issue have cleared up if it was the air box?

Thank you,
John