2007 Ford F150. 4.6L engine. 130,000 miles. Original owner. Loss of power and black smoke out of exhaust. Mechanic changed power steering pressure switch (Something about 5 volt reference to computer causing issue). Worked for about a month then same issue. I unplugged power steering pressure sensor and drove that way for a while. Truck will stall out at stop light or when turning at low speeds but no longer has black smoke and loss of power issues if sensor is unplugged. I replaced the power steering pressure sensor and it ran okay for about 3 weeks then back to loss of power and black smoke out exhaust. I took it to another mechanic, he said bad EGR, replaced. It did not fix issue. He replaced the power steering pressure sensor, worked for about 2 weeks, back to same issue. I was told the catalytic converters were clogged up causing all the problems. I had them replaced today. Did not replace the original muffler. Issue still present.. Mechanic says he knows nothing else to do. I have unplugged the power steering pressure sensor so I can drive the truck. I want to be able to stop at a traffic light without having to pat the gas pedal to keep the truck running. Any assistance is greatly appreciated.

 

I have never heard of this issue before so I don't know if anyone else will chime in... But what do the EGR, power steering pressure sensor, and fuel rail pressure sensor have in common? They are in the same harness and share the same voltage reference supply and the same ground point.. I would be suspicious of a problem with the wire harness like chafed wires that are shorting to each other or to ground or a bad ground wire that just happens to look like it is ok or temporarily behave ok after the sensor is replaced but after the wires relax back to their normal state it shorts out again...
just my theory but I'd be inspecting the harness in that area for damage, chaffing, corrosion, pinching, etc.

Does it throw codes for the steering sensor and nothing else?
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I didn't think we had an EGR.

 

I think the 4.6l does

 

I do not remember the codes the mechanic said were showing. I wished I could recall. Thank you for responding.