When was the kit installed? Did the problem show up right after or a few days after the kit was installed.
All components of a CNG Kit MUST be from the same manufacturer and you must go to a qualified mechanic to get your problem sorted. if the CNG components on ur car are from different makes than u should consider trading them in.
Do not take ur new car around and have people poke around the engine or its wiring without actually knowing wat they are doing.