My check engine came on about 2 months ago. I went to Advance Auto and they hooked it up to the computer and told me it was running lean and the bank one oxygen sensor needed to be replaced. I replaced it and in less then a hundred miles the light came back on. The computer then said it was again running lean again and the bank 2 oxygen sensor needed to be replaced. When my mechanic got my car up on the lift he told me I have 2 bank 2 oxygen sensors. So since I had only purchased one he said he would replace the one and see if the check engine stayed off. It didn't, came back on in 24 miles. Tomorrow I am going to replace the 3rd and final oxygen sensor, however I am worried the check engine light will come back on. I am trying to get it off for inspection next month. If replacing this sensor doesn't keep the engine light off I am not sure what else to look at. I am looking for suggestions or ideas on what else may be causing it to be running lean and what I could do to fix it.
Thanks

 

Welcome to the site..

Sorry about the delayed Welcome..

Oxygen sensors are probably the most 'good' replaced parts. What year/engine?

 

4.0 liter SOHC. I did change the final oxygen sensor and my engine light came back on after 35 miles. It idles really rough and seems like it is going to stall at times.

 

Try a different mechanic at a Ford dealer with a good local reputation ...............I had them chasing my 06 explorer check engine light till I went to a local one , and the problem was the Engine Thermostat not closing all the way , and it was NOT letting the engine warm up enough after a certain amount of time with not very much heat either .

Not saying that's your problem , but money hungry shops with smiley mechanics look for women mostly to keep trying new things till they finally find the defect .............when computers run things in vehicles we're all at their mercy .

Hope you get it found soon , and inexpensive .

John ,