erratic guages/failed smog on 2005 Ford Mustang

I have an issue as my 2005 mustang. It failed smog today with the PO4063 error. I have had a check engine light on for a couple of months, the fuel guage and the speedometer guage are both erratic and not accurate. I am taking it in to a mechanic as I need my car, but am really concerned about getting screwed as I have never failed an emissions test and do not know much about them.

Any ideas what could be wrong or what is required to correct?

Thank you!

Edit Your Reply

Asked by for the 2005 Ford Mustang
1 answer
This is pretty common on the 2005 Mustangs, it's caused by failing stepper motors in the instrument cluster, they control the movement of the gauges. There's a guide on how to fix them here - www.2005-mustang-speedometer-problem.com