Originally Posted by jasoneddy032
I have a 99 Camaro 3.8 and I'm getting horrible gas mileage I had it put on a diagnostic tool at Auto zone they said the codes that came up were for one o2 sensor left bank sensor 1 and a random misfire code so I changed the o2 sensor it made no difference the car still get horrible gas mileage but other than a slight hesitation from a stop and bad gas mileage the runs and performs fine any ideas would be greatly appreciated
First, Welcome to the site.
Define "horrible gas mileage". Have you actually checked it? If so, what is it?
Yes, as already mentioned, the misfire needs to be fixed.