Recently aqquired dodge durango

I recently aqquired a 2000 doge durango 2-wd slt with the 5.9L engine. it had some minor problems such as cat. converter was plugged and it has an ideling and acceleration problem. I have done alot of reading and I have found that people seem to be spending alot of replacing things and not getting the problem fixed. I cannot afford for this to happen so I have spent the last 4 weeks doing research.I think I have found the problem. It seems to be the o-2 sensor heating element has a ba ground. I have not performed the repair as of yet, but I will keep up with the progress.
I also recently spilled 1 gallon of gasoline in the rear of my durango. this is not a good thing. I spent an hour and 2 rolls of paper towels trying to pull it up. It ran all the way up to the second row seating. I have had kitty litter on it now for a week. It has helped tremendously in pulling the gas up out of the floor. but the smell is BAD. I am trying to avoid havint to take the carpet out, but it is not looking good. If any body has any ideas, I'm open for suggestions.