OK GUYS really need some help here!! 2004 mitsubushi endeavor has oil pressure idiot light no pressure gauge. problem: very noisey valve lifters and oil light on check engine light came on about two days ago, did oil change about two weeks ago about 87k on v6 otherwise engine runs great smooth, has all power but sounds like a diesel engine (it's a gas motor) engine ran fine after oil change and had no issues,one strange thing Iput quart of STP in and loose load lifter sound went away, then I drove vehicle down the block and sound came back in a short while. Anybody?? Please...