Drop in Oil Pressure
I have a 2001 Jeep cherokee (135K). Recently had an oil change at a auto mechanic shop (one of those chain-stores) and few days later started seeing fluid leak marks in the garage. Did not want to go back to the same shop as I was pretty sure they had a plan for me to rip me off and they would not fix the problem. Anyways, soon after oil pressure started to drop to zero ('check gauges'-lights up) whenever its idled and I take my foot off the gas. I saw that this happens only when the temperature reads 210F and not when the oil is still cool. I was praying for a clog to clear out or a non properly fastened seal, valve somewhere during the oil change. So i got another oil change at a different location and nothing changed.
Oil level seems to be fine. Checked it multiple times.
When I took an hour long drive on the highway, the pressure gauge started to become unstable after may be half hour of driving. It is random but it would swing between 40 (normal) and 10. Other than that it was a little scary I did not encounter any other issue running the Jeep.
Is it a faulty guage or oil pump or the sensor? Am I in a dangerous zone?
I would sincerely appreciate any suggestion and greatful if someone can recommend a good mechanic that I can trust to do the job. I live in High Point, NC.