micsteam

I've got my girlfriend's brother's 2003 Chevy Express 2500 van with the 5.3 in it, it has apprx. 115,000 miles. Ever since he bought the van (at apprx. 90,000 miles)his oil pressure has been somewhat erratic and now we can hear a slight tapping which sounds like the lifters are being slightly starved. Is this a common problem on these vans ?? If so what's the general fix ?? We feel an oil pump replacement with an upgraded pump (we would like to use Melling's #10296) might solve the problem or band aid the situation until we absolutely need a replacement or rebuild. Also where's the oil pump on these ?? It looks like it is attached to the front of the engine block and is driven off the the cam or crank. How do you replace one ?? I'm sure I can figure it out but I don't have the van here and want to make all the right preparations to do the job (ie. gaskets sets, etc.). Any and all help is greatly appreciated. Thanks