A few months back, my 2000 yr 5.4 was having some performance issues. I changed out the plugs and ohm'd out all the COPs'-of which read 1.2 ohms each. Performance issue was resolved, but now, when I let the engine idle after reving up, the RPM falls to 400 and the oil light comes on. Engine will recover, but sometimes I need to hit the gas to get the oil light to come off and it typically won't drop until I throttle up and let go. I have 96,400 on it and I've owned it since 75K. I keep the engine compartment clean, and since this is a recreational vehicle, it is not driven but every month or so.

 

Disconnect the battery and turn on the headlights. This will reset the computer then see what it does. The computer may have made adjustments for the old COPS and plugs.

 

Possible the oil pressure switch is getting sticky. If your R/V is like most I've seen, they do a couple hundred miles a year and don't move more than 2 or 3 times a year also. This brings up the old adage, "use it or lose it". Most r/v related problems I've seen are due to humidity and rust eating things apart. Your pressure switch is probably hanging up and is sensitive. Now, low rpm can potentially set the light, as the engine turns more slowly it turns the oil pump more slowly too. However, this should under no normal situation cause the light to stay on once rpm's recover. My best suggestion, R&R the pressure switch and try it again. If it happens again, connect an oil pressure gauge instead of the switch and check actual pressure when you poke the gas. Then you'll know what's really going on.

 

Just a reminder, the in-dash gauge is only a mechanical indicator of a minimum amount of pressure, something like 4-6 psi. It does not measure pressure.

The switches fail frequently. I'd recommend replacing yours.

Steve

 

I was recently able to apply the advice given and I thank everyone for the suggestions. I did reset the computer as instructed and the engine rev down from high rpm seems to have stablized to around 800 rpm at idle. I ran for about 45 minutes with an occasional rev to about 3000 rpm and at each time, it rev'ed down to 800 and never felt like it was going to stall. The old COPS ohmed out at 1.2 ohms so I only replaced the plugs....computer still needed to be reset for the new plugs I guess because it seemed to of worked. The oil indicator dash gauge still goes to 0 with the light on-momentarily. This occurs now even at a clean idle. I would like to try and replace the switches but I need to learn more about switch locations and was wondering if anyone can turn me on to a good resource for component placement so I can work on replacing the oil pressure switch.