Whatever you do, get that confirmed! Low oil pressure is very bad for your engine! You can spin a bearing very quick, causing your engine to seize up. Then you might have to replace the crankshaft, maybe you will have to have your rods replaced or machined as well. Spend a few bucks now, save alot of bucks later! The mechanic just removes your sending unit, puts his in and confirms the pressure. A new sending unit only cost about $25, mechanic may charge about $50.00 for labor. If your mechanic finds the pressure to be low, then possible causes are...
1.) Clogged oil pick up screen
2.) Bad oil pump
3.) Worn engine bearings
or
4.) Bad sending unit.
If you can replace these items yourself, you'll save lots of cash in labor. Cost of these parts are from my neck of the woods.
!.) Oil pick up screen about $15.00, or free if you just pull it and clean it yourself.
2.) Oil pump about $50 or $20 for a rebuild kit. Oil pump rebuilds are easy, just replace two gears, a spring and a little tiny metal marble called a check ball.
3.) oil pan gasket about $25
4.) Engine degreaser about $2 for a big honkin spray can worth of clean!
5.) Oil filter $5 for a good one
6.) 5 quarts of good oil about $15
7.) Engine rod bearings about $10
8.) Main crankshaft bearings about $50
9.) Oil sending unit about $25
Plus tools if you don't have them, just your standard set of metric sockets, rachet, extensions, floor jack, jack stands (get good ones!), hammer, trouble light, pliers, screwdriver set, old clothes to wear, plastic sheets to catch oil drips and...
10.) a good repair manual about $15, or loaned to you for free at your local library! Be sure to keep it clean
!