Yesterday as I was pulling in the driveway, I noticed the "Check Gages" light was on, and looked and saw that my oil pressure was almost at the bottom.
Well today I checked the oil, and it was well above the add mark, and it was a goldish brown color, so it's pretty new oil. (1'500 miles since my last oil change; always change my oil every 3'000 miles).
In the past when I'd crank up the truck, when the engine was cold, the oil pressure would go up to about halfway between '40' and '80'
(seen here) http://i41.photobucket.com/albums/e285/DMD333/S5030065.jpg

When it gets warmer, it goes down to a little above '40'.
(seen here) http://i41.photobucket.com/albums/e285/DMD333/S5030033.jpg

But now when I start it, it starts out halfway between '40' and '0'. Could my oil pump be bad?

Usually it is a oil pressure sending unit problem.
But you need to put a manual oil pressure test gauge on it to find the true pressure.
A electric gauge is only a indicator gauge.
Post back what you find.
MT

Usually it is a oil pressure sending unit problem.
But you need to put a manual oil pressure test gauge on it to find the true pressure.
A electric gauge is only a indicator gauge.
Post back what you find.
MT

I agree the sending unit is the most likely problem, but why not just change that out for under $10 and see if the guage returns to normal parameters before doing a manual oil pressure test. A manual oil pressure guage, or a trip to the mechanics to test it will cost a lot more and will probably point right back to the sending unit, and how often is the average person going to need a manual oil pressure guage in his lifetime.

That procedure might save you a few dollars but could cost you a engine.
If you want to do proper testing and see what the true oil pressure is you will need to put a manual test gauge on it.
Anything else or just throwing parts at it is a hit and miss.
MT

you cant just go throwing parts at cars and hope they work doin it right the first time is always cheaper
remember you can go to autozone and borrow tools so you wont have to buy a guage

Thanks all. Yes, twas the sending unit. Costed $99.82 to have it replaced.

You are welcome and .
Thanks for posting back how it went.
Did they check the actual pressure on a test gauge or just throw on a sending unit?
MT