Hey guys and gals,
Newbe , I am going to replace the o2 sensors on my 1.8 liter mirage es. Which one is usually the problem one after or before the cat. I am trying to save alittle money by relpacing the the most common one that fails. I have not run a scan tool but the milage has dropped off by at least 5mpg. The cat is fine no power lost but just the milage. The car has about 86000 miles on it now.