Could use some help with starting problem 7.3 deisel
My father's truck is having some starting problems. It's been going on off and on now for about a year, but seems to be worse. The truck is a '99 F-350 with the 7.3 diesel. It doesn't have many miles on it for the year, 135k or so. He uses it mainly for plowing. I bought the truck in '04 and he took over a couple years ago. We've always maintained it well and we never beat on it.
It used to start really well with no problems, and then it seemed like after I put a power programmer to it (I can't remember the manufacturer, but one of the major ones) it started to take a bit longer to start, maybe 5 or 6 seconds vs 3 or so. I had it on the 'fuel mileage' setting when I wasn't towing or plowing, and at idle, it would idle really inconsisantly, and almost stall at points until it was warmed up, eventually, I put it back to the standard configuration and ditched the programmer. Not really sure if it helped or not.
We've had the truck just cut out at times as well, we would be driving a long, and under a light load fairly consistant driving (under highway speeds) it would just stall, this only happened a couple times. We thought maybe it was the fuel filter or air filter. So he changed the filters.
We've still noticed problems starting it, sometimes it will just be a really low battery, seems like the battery may be draining from something or not holding a charge, so we bought new batteries.
The problem seemed to go away for a while, then creep back. At one point it would just click, so eventually he changed the starter and it seemed fine.
What is happening now, is that he will go to start it, and it will start maybe 5-10 times, and then when he goes to try starting it, you will hear a solid click at the starter when you turn the key, the batteries are both fully charged.
He ran a new wire from the starter solenoid to the relay that is on the fender wall and cleaned up all connections. If he disconnects the pig tail wire to the solenoid on the passenger side fender wall, and puts a new wire on, and jumps it with a screwdriver at the solenoid, it starts easily. But then it happens again. At this point we don't know what to do. He is very mechanically inclined and was a mechanic for years, however that was a long time ago before all this fancy electronic stuff.
I remember reading on here a long time ago about the cam shaft sensor. I did recommend trying to change that first but he is stubborn and didn't listen to me

Do you think that could be the problem? I know there is no sense in NOT trying it since it's a cheap part, but want to ask you pros first. I remember reading some threads on different ones to get and not get, but now I can't seem to find those threads. Should he just order one from Ford? Are there different 'types'?
If you do recommend the next step to be the cam shaft sensor, are there any 'go to' threads describing how to change it?
The following has been replaced within the last year or so:
Starter solenoid at fender wall (is there another solenoid somewhere.)
Battery (starting)
Fuel filter
Oil filter
Alternator-twice (the first replacement was bad but covered under warrenty)
Starter
This is how he worded the problem to me:








