I have a 2006 F150 4.6 L vin code W. The oil pressure needle started fluctuating and finally went all the way down and the valves started tapping. Would this be caused by the oil pump going bad or could the oil sensor be bad . Thanks .

 

I think you have an oil pressure problem, not a gauge problem. This is because you got typical oil-starvation noise from the valve train. Better not drive it until you find the cause. Have you had the truck for a long time or is it recent? If you don't know the oil change history or what has been used in it you have to start from scratch. First, check the oil to see if the level is good and it doesn't look too bad. Then, replace the oil filter with the Motorcraft one and see what happens. If the noise stops and oil pressure returns, you're done except maybe for an oil change. If its still a problem, you need to prove it has low oil pressure by using a mechanical gauge. If the engine has a lot of sludge in it, you could simply have a restricted pickup screen - try to look into the rocker cover to see if it looks sludgy. If it looks clean you may not have a sludge problem although at this point I would be inclined to use a solvent in the oil to see if a restricted oil pickup screen is the cause. If the oil pressure then improves, you could continue to treat it and make a few oil/filter changes or drop the pan and clean everything the right way. It could also be a bad oil pump or pump drive - I'm just saying what I would do first before tearing it down.

 

Thanks for the reply. I've owned the truck since new and changed the oil regularly. It has clean oil and to the proper level.