I've done some searching and haven't found my problem yet, so I'll post it and face any "Why don't you use the search button!" ridicule I get.

I have a 2003 F150 SuperCrew. 4x4. 5.4. It has 27,200 miles on it, and I'm the original owner. About 2 weeks ago, I got the LOF at Valvoline. Two days later my S.E.S. light came on. The truck runs fine, mileage hasn't changed, etc, etc.

I went to Auto Zone today to have the codes pulled. Two codes, both telling me that I'm running too rich (one for left bank, one for right bank). No, I didn't write the numbers down; that would have made WAY too much sense.

Any thoughts (other than keep searching?) I have a shop that I trust, and they'd probably plug it into their machine to give me a better idea. Just wondering if I should try something else before paying them a visit.

Thanks!

 

There is a few scenarios that will give rich codes. If I was to look in a particular area, I would start with your coolant system. If the pcm sees cold temperatures, it richens up the fuel/air mixture to accellerate warming up. If you can get to a scanner that will show you the data stream, look at the ect sensor. If it was unplugged, it will show something like -420 degrees. That will give you an idea how that can change the pcm response.

 

I love the old, "ever since" story........ And I believe those codes would be P1171 and P1172?

 

Yep, exact codes would be most helpful.

 

Check your pcv line at the manifold. The elbow back there is known to break & cause a lean code.

 

You mentioned that your truck is 2003 with only 27,200 miles on it, go take it back to the dealership, chances are your vehicle is still covered by ford emission warranty. I know ford have 5 years or 50,000 miles warranty with their emission.