I've got the same truck as the original post; 2003 1500HD 4x4 crew. shortbed. 6.0 within maybe the last two weeks the truck has been making this kinda faint knockin sound. (maybe a bad lifter?) i dont know not really a wrench myself. but it gets a little louder as the rpms climb and then softer when they go back down. guys i got no idea what to do? i could work on my old chevy's but these new ones should come with a keyboard and a mouse man. . . any ideas??

 

Low oil pressure - 2003 chev 2500hd truck. We have changed the oil pressure sending unit and oil pump. The sound alert is still on and it will not go away. The oil pressure guage is alittle above 0 and when you accelerate, the sound alert will stop and it oil pressure guage goes up to 40. Help, what is the issue?