Ok, good. There is a PCM software update for this condition. You are probably not really loosing oil pressure. This is an electrical/software issue. Take your truck to the dealer and ask them yo update the PCM for you. They should be able to do this for under $100.00. Here is the TSB that discusses this issue, and I hope this information helps. Let me know if you need further assistance with this.
DATE: December 28, 2001
THIS BULLETIN IS BEING PROVIDED IN ADVANCE. THE MDS2 MUST BE OPERATING
WITH CIS CD 2101 OR HIGHER, AVAILABLE FEBRUARY 18, 2002.
Multiple Vehicle Performance and Durability Enhancements
This bulletin involves selectively erasing and reprogramming the JTEC Powertrain
Control Module (PCM) with new software (02Cal19D).
2002 DR Ram Truck
NOTE: THIS BULLETIN APPLIES TO 2002 (DR) RAM TRUCKS EQUIPPED
WITH THE 3.7L, 4.7L OR 5.9L ENGINES.
Some 2002 (DR) Ram Trucks equipped with the 3.7L, 4.7L or 5.9L engines
may exhibit one or more of the following conditions:
1. Any of the trucks shown above may exhibit a condition wherein the oil
pressure gauge intermittently drops to zero.
NOTE: THERE IS NO RISK OF DAMAGE TO THE ENGINE WHEN THIS OCCURS.
2. Any of the trucks shown above may exhibit a fuel gauge error that leads the customer to
believe the fuel level is lower than it actually is. This condition is most often noticed
when the customer is filling a fuel tank that is less than half full.
3. Some trucks equipped with the 4.7L engine may exhibit spark knock
at or near wide open throttle.
4. Some trucks equipped with the 4.7L engine may set an erroneous P0131 fault code
(1/1 Oxygen Sensor Voltage High) due to extended closed throttle engine operation at
higher than idle RPM (extended downhill coast). This change will cause the oxygen
sensor heaters to come on, eliminating the erroneous fault code.
5. Some trucks equipped with the 5.9L engine may exhibit a transmission
overheat condition when the vehicle has been under continual load conditions
(i.e. uphill towing). This software change will ensure torque converter lock
up in 3rd gear to help minimize the problem.