I have a 2003 z71 i bought new it now has 66,000 miles and i replaced the oil pump 3 or 4 months ago and this thing went from useing no oil to where i am constantly puting oil in it. I have no leaks that i can see and it doesnt smoke maybe a little when its dark i can see some in the headlights behind me . I put a melling high volume oil pump could this have caused any problems it has awesome oil pressure . I have always used Mobil 1 Synthetic . Any suggestions would help . ](*,)