Could be low oil level or faulty sensor. The 2.7L intrepid oil pressure is considered good if the pressure stays above 5 psi. Normal oil pressure at 3000 rpm is above 45 psi. If the pressure sensor diaphragm leaks while running it will build up pressure on the outside of the diaphragm on the connector side. When the engine returns to idle the outside pressure will cause the sensor to momentarily falsely detect lower than 5 psi and turn on the light. If the sensor leaks oil, replace it. Also if the engine has greater than 75,000 miles using full synthetic 10W40 motor oil will increase the idle pressure by about 5-10 psi versus 10W30. Mine was reading 12 psi (with a gauge) and increased to 20 psi with the heaver weight oil.
I temperately installed a mechanical oil pressure gauge to determine what I had for oil pressure. With the engine warmed up, idling in drive, I had 18-20 psi. This is good but the light would still flicker even with a new sending unit.
Disconnect the electrical plug at the oil pressure sending unit. Notice the unused spaces for extra wires that are plugged with rubber dummy plugs. Remove one of the dummy plugs in that connector and reconnect the plug and your problem is solved. I seen a TBS (Technical Service Bulletin) addressing that problem. It seems the oil pressure from the engine not only has to over come the spring inside the sending unit which is normal but it also has to compress the air trapped inside the weather tight connection which is not normal.