55mm to a 70mm Mass air meter

93 Cobra's had 24 pound injectors, I seriously doubt it was calibrated for 19's. Thats more than likely the problem.

The original cobra mas's were calibrated for 19# injectors, and the computer compensated for the 24's that were in the car. It should work with your 19's, I know someone doing this with no problem. Did you remember to reset the computer after you swapped the meters? Disconnect the - battery terminal and turn the headlights on for 10 minutes or so.. then turn the headlights off, reconnect it, and then try starting your car. (the headlights are just to make sure all the voltage drains from the system) There's also the possibility that the meter is bad.