Oil pressure

The first thing I would do is have a mechanical guage put on it....most likely your electrical gauge is screwed up else you would be complaining that your engine sounds like a 1000 woodpeckers on a tin roof!

Well let me tell you....I had the same problem....Chevrolet says that the oil pump was designed around the fron of the crankshaft....therefore they assembled the sump filter with oringed piping!! My engine completely locked up......and was told the only solution was to replace the oring...as this is where you loose the suction at low RPM's!! Have a qualiified Chevrolet mechanic check this for you!!

As other posts recommend, the first thing to do is try a master guage to get the actual pressure. If this reads normal could be the sending unit (had this happen on a 90 Pontiac-had the same symptoms you mention). If the actual pressure is low could be several things-faulty pump etc. Don't want to mention it but had the same thing happen on a 77 GMC 454 and turned out to be worn main bearings-rebuilt engine and installed high volume pump with racing oil.