Update on my oil pressure light on idle.
After all the nasty job removing my oil pressure switch, the time I spent under the engine, the hunt for original oil pressure switch & the cost of the new replacement oil switch, I DID NOT FIX THE darn PROBLEM.
I capped (plugged) the original oil pressure hole (stupid hole). I installed a TEE adapter on the spare hole in front of the oil filter housing, I installed an analog oil pressure gauge then the new replacement oil pressure switch (see picture).
I started the car, the oil pressure reads 50lbs (engine cold) I drove 3 miles and as soon as it idles (engine hot & 86 degrees here in Florida yesterday), the oil pressure light ON in idle !! WTF!
I was so ASHAMED to tell you that the problem was not the oil pressure switch nor the suspect of bad oil pump. The problem was simply my car idle so low and the oil pump pushing only 20 pounds of pressure (light turn on below 20psi). The Esprit is notorious idling low in a very hot environment like Florida. As soon as I turn my AC, the idle even lower. I used to live in cold weather of the state for many years, then I moved this year to Florida.
So the solution, I simply raised the idle to 900/1000 rpm and my oil light never turn on. Its now 25 pounds idling (very hot engine). No oil pressure light on.
STUPID ME I OVERLOOKED --------->Thank you all !!