My guess would be that the CEL and especially the battery light have nothing to do with the gasoline. If the battery light is coming on at all, it's because there is a problem in your charging system (battery, alternator, alt. and batt. connections, etc.) As for the CEL, you need to get the codes that are stored (I forgot how to go about doing this in an OBD1 vehicle, perhaps someone else can chime in) and post the codes so that we can look them up and tell you what the problem is.