So it's been doing this for a while...

My understanding was our oil gauges were simple dummy lights basically.. but mine acts weird...


I really want to just get a mechanical gauge, I don't feel very trusting in this wonky gauge...

 

I have a friend that has a 94 5.0 and the gauge did that. His motor went about 2000 miles after he noticed the gauge was doing this at idle and everytime he let off the gas. Does you truck have any blow by at the dip stick tube?

I would do a oil change and add a full bottle of lucas oil stabilizer. See if it changes.

 

I vote bad sending unit. If the oil pressre dropped out like that, you would here the death rattle of a dry engine at zero pressure very quickly. Mechanical gauges are great, but try a new sending unit for $5 at your local autozone. Takes 10 minutes to change.

 

Mine flatlined about six years ago, no problem. If it has no oil pressure really , theres a rod that pops out after a while.
Its probably a bad sender, wouldn t hurt to try that, or buy a cheapy pressure gauge and see if it has any pressure. I have one from wall mart i just screw in things to check , cost like ten bucks.

 

Replacing the stock sender costs $11 at my local stores, putting in a Sunpro electrical Oil PSI gauge cost $23. So I'd vote just put the aftermarket gauge in. It seems like your sending unit might be going out, or your gauge could be getting old. I know that when working properly, the oil pressure sensor is just a switch, when pressure is above ~6psi it sends the gauge a signal, when below 6psi, the gauge does not turn on.

So worst case scenario, you are losing oil pressure everytime you let off the gas. Best case scenario you just have old electronics and can replace them with real gauges noq

 

Ok, so if I look at worst case scenario there, install the mechanical gauge and find out that it is losing pressuer when there's no gas, what would that be a symptom of?

 

Worn out oil pump, or worn bearings bleeding off pressure.The slower the engine turns the less the pump pumps, so low pressure at idle.
The old rule of thumb for oil pressure is 10lbs per 1000 rpm.

 

You could have the best of both worlds. Replace the stock sending unit. If it works, great. You maintain your factory gauge so you don't have a dead gauge on your cluster. Then for a few bucks, you can add a dual outlet setup at the block and install a mechanocal gauge for exact psi and maintain your stock cluster. I have both and I spent about $30 total. I jist have a thing about keeping your stock instruments in working order, even with aftermarket gauges installed.

 

I would have done that if I had found the T-fitting, but then I figured 'cause my gas gauge doesn't work either, wasn't too big of a deal

 

I found a tee on ebay for $10, but ended up going to Oreilly and they built one for $3.