02 Taurus Oil light is on at idle when warm.

The ticking noise could be a faulty hydrulic valve lifter. When last was the oil & filter changed, it coul be that the oil is thick and not going through to the lifters and when it warms up the oil is thin. It could be that the engine is need of an overhaul as 148.000 miles is 238.182 Kilometers and that is a hi milage.

This sound like you have either delay on internal lubrication to tappets,most probably due to correct oil either change or viscosity.
In how many miles you do change the oil ? Just do an engine oil flush and a engine oil & filter change using also a viscosity improve and follow for a different engine behavior.

I think your correct

It may be valve cam bearing noise

Not much you can do --unless you check
bulletins & then take it apart

it is a lifter sticking till motor gets warm it happens in time i know a trick put i help so much for free.it will be fine try a highmile oil and check it every fill up my be low.

MINE DOES THE SAME THING. IT SEEMS TO ME FORDS ARE BAD TO DO THAT AFTER THEY GET A LOT OF MILEAGE ON IT. MINES USUALLY GETS QUITER AFTER IT WARMS UP. SOMETHING THAT HAS HELPED IS HEAVIER OIL (20/50) AND SOME MYSTERY OIL.

The ticking could be a spark plug wire shorted out to ground of which you can watch in the dark while the car is running and see if you see a plug wire jumping to ground which will look like a lightening bolt hitting the ground. It could also be a lifter making noise. Could be a exhaust leak. What is your oil pressure? Does your gauge tell you pounds of pressure or is it just a light?

I would have to say your engine is probably shot. The bearings are probably gone. It is possible, i suppose, that your oil pump is faulty. As soon as the oil warms up, and becomes thin, the rods and lifters start to rattle. The same goes for the oil pump, as oil becomes hot, and thin, it may not be pumping properly. I would try a used oil pump, and see if there is any difference before i wrote the engine off.

DOES IT HAVE A LOT OF MILES ON IT OR MAY BE THE OIL PUMP IS IS GOING OUT? THERE IS A SPRING IN THE PUMP THAT IS A BYPASS FOR HOW HIGH PSI IT MAY HAVE BROKE THAT WILL GIVE YOU LOW PSI.

Here goes:
Please do not drive the car.
Have the car towed to a well-recommended garage
Have someone unscrew the oil pressure light or gauge sending unit in the engine block and screw is a oil pressure guage ( hand held, used in garages).
Test that pressure carefully at all speeds.
Either you have: a bad oil pump, a plugged oil filter, a clogged oil passageway, or a bad engine.
The ticking sound might be valve lifters that are not receiving oil.
God bless your efforts.

Is this lower left as seen from the drivers seat?