I bought my 99 f150 a year ago it's been running good bout 2 weeks ago it started losing oil pressure,so a buddy of mine who claims to be able to fix things looked at it then he put on a camshaft position sensor it ran good for maybe 50 miles engine light blink rapidly for couple seconds I shut it off when he took things apart the gear/sprocket that goes on end of camshaft was chewed up or ground down this is the fourth time this has happened what could be making this keep breaking

 

Well your not getting any answers to your issues.
What you report is confusion.
First, the cam sensor has nothing to do with oil pressure. It times fuel injection.
If it is being damaged, suspect the cam shaft to have excessive end play. Remove the valve cover and see what's going on, then what repair is needed. It is possible the cam bearings areas are\has been damaged and could affect oil pressure. In this case the head/s are lost unless bearing insets are machined for and used.
Side note: I just stripped an engine for the block that was run with no oil or pressure. Everything was ruined, heads, crank, cams, nothing survived but the block but that's all I was after.
It is alum. for light weight buildup for performance race application..
.
Put a gauge on the oil filter port in place of the pressure sensor and see what you have. A good engine will have about 25 psi on hot idle but lower pressure will still be ok but suggest there is a reason the pressure is lower. Aged engine, bearing clearance is getting larger etc.
.
Flashing CEL indicates a cylinder has lost ignition. To see which one, use of a Scanner to look at data (not code) will show the cylinder with the highest count as the suspect.
Bottom line is you cannot fix things without doing diagnostics, from a mile away but get in and see what's going on.
Guessing does not fix anything unless your lucky.
Your at a point this needs to be done or the engine will be toast in a short time.
Good luck.

 

I have.a 99 f150 with a 4.2 I've changed the cam shaft position sensor twice now going on 3times and the gear that used to be for distributor drive but now is for cam shaft position sensor it and the gear/sprocket on position sensor are badly work or grounded out (gear looks like someone took a grinder to it) any idea what is causing this to keep happening,and also the other day while driving I noticed engine light was blinking faster then I have ever seen please help me

 

did you remove the valve cover and look at the cam and bearings as Bluegrass suggested ? You have a problem in that area.

 

My answer was based on a v8.
Now you say it's a v6.
Totally different cam drive.
The unit has to be set in so the sensor is in the correct position and fully seated on the block.
Under the gear is an oil pump drive shaft.
They all have to be meshed end to end all the way down to the oil pump or you cannot fully set the unit down on the block and tighten the hold down clamp.
Is it? Or are you disregarding and forcing it down.
If not all seated the oil pump will not be turned from the cam shaft gear. That means no oil pressure.
Your not doing something correct.
Now you likely have bronze or cast steel chips in the oil pan.
Better let a shop do the work if the engine is not already toast from foolishness.
Good luck.