Tow it home. Get a mechanical gauge on it. Start it and see what you 'really' have. I have a similar problem. After driving 15 minutes, mine will drop to 0 at idle, but is fine at throttle. I put a mechanical gauge on it, and turns out after it warms up, my pressure drops to around 10psi at idle, apparently too low for the stock gauge to read. I think it's my bigger cam, but not sure. Hopefully you're is something simple. You could pull a valve cover also, and see if it's pumping oil.
Verify that you do or do not have oil pressure. That should be easy enough. Then check your wiring fromthe sending unit to the guage to ensure you don't have a wire laying on something hot. You can check out he sending unit with a multimeter (or just replace it. It's cheap). replace the guage if it's the culprit. If in fact your oil pump is bad then replace it (not so easy). The ticking noise you describe leads me to believe that you do infact have an oil system problem which means (most liekely) replacing the pump. I can't imagine anyone who changes their oil regularly having a blockage that is as sudden as you describe (unless something in the motor just broke and skattered debris through your engine). If it weren't for the ticking noise you describe, I'd say run a higher weight motor oil and see what that does to your guage. Still... if you rule out the indication system then it pretty much limits what's left huh?
pull your distributer and check and see if the shaft from the dizzy to the oil pump is broke it happened to me.think a shaving from the head job was in the oil pan and locked mine up .the ticking you hear is probably from the lifters cause there not getting any oil.i wouldnt run the engine anymore till your sure there is not a major problem.and yes its a pain to change the oil pump unless you have friend with car lift and some real long screw jacks and it still sucks. i woulld recommend pulling the trans and h or x pipe if you have one dont remember from reading your post.
SleepinGSR said:
Piece of pie... Take an ohm meter and run it from the sending unit post to ground. You should get nothing (open circuit). Start the car and let it idle. Take another reading (watching your fingers and extremities). You should get anywhere from 55 - 80 ohms on your meter. 'What' the reading is isn't really all that important (they're not very accurate units and tend to vary widely). If you get a reading anywhere near the range I listed then it indicates that the sending unit is at least functioning.