I have a 03 1500 and today i lost oil reading on the guage.The truck is due for an oil change but the oil level on the dip stick was still good.I'm thinking i have a bad oil pump,but i want some opinions thanks.

 

Usually it is the oil pressure sensor. It is on the oil filter housing. i would rec. starting there.

 

Thanks i will start from there first,and i will keep you posted.

 

If you've got the 4.7, they are notorious for getting gummed up with sludge over time, causing oil not getting up where it needs to be. Drop the pan and have a look/see. Clean it out good and then a little Sea Foam treatment should do the trick.
MMStar23 had the issue and has quite the lengthy thread in this section detailing it and his fix a few months back. Do a search - good reading...