I have a 95 2.5L, completely stock. I keep getting engine codes 24 (TPS), 21 (02 sensor) and 51 (02 sensor). I changed the oxygen sensor about 7,000 miles ago and the light went away for a while. It came back with the same codes so I changed the TPS sensor about 3,000 miles ago and the light went away again. Now the same codes are back. Could there be anything underlying that's causing this. Someone told me it could be carbon build up (my engine oil does get dark quicker than it should). Would a good throttle body cleaning and maybe new injectors work? The engine has about 107,000 miles on it.