Chevrolet Repair: GMC Jimmy oil pressure drops/tapping or knocking sound, low oil pressure, gmc jimmy

Question
Hi, I'm not sure if this is the type of question you can help me with, but I will attempt to explain what my truck is doing. Up to a month ago, my 1999 4x4 jimmy ran great. I had an oil change at a Big Box Store,not mentioning the actual store name, but they forgot to tighten my oilpan plug,therefore losing app.3-4 liters, now I have a tapping or ticking noise and after 15 or so min. of driving my oil pressure goes down, what kind of problem do you suggest this could be, and how to fix this would be of great assistance.  Thank you

Answer
Hi Tammy.... i hope you went back to that store and told them they didn't do the job right or at least had the place where you had the oil plug tightened document the problem...it sounds like when you ran it low on oil you damaged something inside the engine... low oil pressure can be caused by wear from lack of oil.. i would take the truck to a garage you trust and have them check it out...explain the problem as you did here, get them to document it and go back to the box store and have them pay for the damage. big box stores use cheap unqualified labour and their negligance may have damaged your engine...hope this helps