shouldnt my oil pressure rise?

so ive noticed a weird trend with my oil pressure and its got me wondering whats doing it. she idles right above the 20 mark, when cruising she will sit just over 40 or so on the gauge. when you increase speed i figured my oil pressure would rise a bit more towards the 60 mark. instead it drops alittle below the 40 mark and then when im cruising to a stop goes up to 40 or so then slowly drops to around 30. i replaced the oil pressure sending unit with an OEM part back in sept. is it time for a new one? i just got an oil change and checked my oil level and its in the safe area so i should be seeing positive pressure... at least thats what i thought. thoughts?

That is a little weird how the oil pressure drops at higher rpm's (but you're saying higher speed, not higher rpms). It's still good though. This hasn't started just since your last oil filter change, has it? What oil and filter are you using? Are you sure the pressure isn't going down a touch when it shifts into overdrive and the rpms drop. The oil pump speed is related to engine rpms, not ground speed.

no even when i am speeding up(increasing rpms) to say merge it doesnt move it hangs at 40. i figured id see it jump alittle. im using a larger wix filter than the stock size, so it added alittle extra oil. as far as oil im using pennzoil 5w-30

It seems like you're doing everything right. Your oil pressure is still good. You couldn't have just one bad filter, could you? Was this situation also on previous filter?
I wouldn't worry about it, but next steps to try would be new oil pressure sending unit (as you suggested) and then new oil pump. But like I said, I wouldn't do anything. Just for jollies, you could see what happens with Rotella 15W-50.

bump, more input

i would verify the oil pressure readings with a mechanical gauge. run it onto the hood and tape it down you can read the gauge when you drive.

89xj said:

i would verify the oil pressure readings with a mechanical gauge. run it onto the hood and tape it down you can read the gauge when you drive.

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oil pressure doesn't need engine under load (moving), it just is dependent off the engine turning at a certain speed, the pressure spring, and other factors inside the engine that's generally engine rpm dependent.

At idle with engine all warmed up (idle for 10, or drive a few miles) 20psi is good.

When the engine is revved (1500-2000rpm) it should read around 40.

If it's cold (winter) sometimes mine will indicate about 50, but I haven't seen it any higher.

89xj said:

i would verify the oil pressure readings with a mechanical gauge. run it onto the hood and tape it down you can read the gauge when you drive.

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Yup, only way to know if the readings are real or not.