Answering #2's questions

Hey Jana, There just isn't enough info to go on here. To diagnose this problem you will need to run several tests and see any data that is stored in the engine module, as well as read out the input and output signals from engine module. Fuel pressure and volume needs to be checked. You will need to find a good shop that has extensive experience in diagnosing these types of problems. The slight miss you mention may be contributing to the Cat. Conv. failure, so that need to be addressed, and it is a good place to start if there are no codes stored. Just a note, there can be codes stored even if the light is not on.