Q: Engine running rough - 2001 Ford F-150

asked by on November 07, 2016

CEL came on, scanned and codes P0131 and P0151 came up. Replaced both upstream O2 sensors and fuel pressure regulator, still runs and idles rough! Any suggestions?

My car has 160000 miles.
My car has an automatic transmission.

Hi there. Have the codes returned since the repair? It sounds like the valve timing control valves are sticking. The valve timing control valves control oil flow to the valve timing actuator and are a duty cycle type controller. The mileage you have is ideal for one or both of these to start having some issues; especially if the oil changes haven’t been performed regularly and on time. You can remove the valves and move the internal shaft to see if it has resistance to being moved; there should be no resistance and it should move easily and freely. I strongly suggest having a qualified technician perform a diagnostic to avoid replacing unnecessary parts. YourMechanic has several available technicians that can assist you with a rough idle inspection if you need further help.

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