If when you try to check ECM codes on a 1994 Corvette it fails to connect and now the check engine light goes on-and-off and the car is running rich could it be your ECM went bad?

Answer 1

Flashing check engine lights on GM vehicles indicate cylinder misfire. There are many reasons an engine may "run rich" but bad fuel/air mixtures will cause cylinder misfires. Also, unlike other trouble codes that cause the engine light to stay on, misfire detects are the only cause of a flashing MIL(malfunction indicator lamp). Therefore the ECM will read "blank" when you scan it. You may want to look at spark plugs and wires. O2 sensors may also be the culprit. Check your intake as well, if the engine isn't getting enough air, it may flood itself with more fuel to compensate for the power loss. And that will cause it to "run rich".