Hello, I have a 2002 Chevy S 10 LS 4.3 V6 with 79,000 miles, it developed a lifter tick, at first it only came every now and then, it only lasted 10 seconds , I change the oil and added engine additive and it seemed to go away for two weeks, now every morning I start it, it ticks like mad, and the ticking doesn’t go away for at least two minutes, My mechanic says I have good oil pressure, and he doesn’t believe my lifters are bad I mean how could they be it only has 79,000 miles? He is recommended doing a complete engine flush and changing my engine oil every 3000 miles and putting engine additive, is it possible my oil pump strainer could be clogged even though there’s good oil pressure?  any recommendations any input would be appreciated