1994 4.6L oil pressure issues (possibly severe)

[lilrogue78]

I have a 1994 4.6L (so i figured it could go here too since i have it in the cougar forum aswell) cougar and it has had an oil leak at the oil filter adapter for awhile well just a couple nights ago i accelerated hard and it lost oil pressure at an alarming rate to the point that my check gauges light came on but the pressure came back when it came back to a lower RPM its been doing this ever since that night i have replaced my oil filter so far and it was not the first time i have gotten on it like that either its actually usually way harder and at cruising speeds the oil pressure is great its great at start too (in the "norm" range) if anybody has any ideas please help
dave

[97Bird]

Are you low on oil? Where is the level on the dipstick?

[lilrogue78]

no its full

[Blue)(Fusion]

Sounds like your oil pickup screen is clogged. The tube that extends into the pan from the oil pump has a screen to prevent big chunks of debris or sludge getting sucked in. If this is clogged up enough, it will diminish flow so that it may be able to keep flowing enough oil for low RPMs, but get up in the RPM range and it's like sucking soda through a pinched straw.

Drain the oil and see if you can see any debris/sludge coming out with it. Also look through the oil drain hole as best you can with a flashlight to see if you can see the oil pickup and see if it's clogged at all. If it is, drop the pan and clean it.

By the way, I don't think this was a big problem on the earlier 4.6Ls as it is with the 98-2003 range, but this can sometimes indicate pieces braking off of the timing chain guides and tensioners. I believe your parts are metal and much less likely to break (mine are plastic ), but check anyway by listening for a "sewing machine" sound from the timing chain cover.

Oh and for what it's worth, the dash oil pressure gauge is phony. It just indicates whether or not you have pressure - does not display how much pressure you really have. Stupid, I know. And the leak may be unrelated. Are you sure you had the gasket from the last oil filter off so it's not a gasket-to-gasket seal?