Just bought a manifold pressure sensor off eBay. My first test of these is always to hook up my Mighty-Vac and see if they hold vacuum. This one didn't. But when I hooked it up to the car, it seemed to work fine. While it has the same Bosch P/N as mine, the air inlet configuration is slightly different than mine. Also I remember vacuum testing the sensor on my friend's parts car and that didn't hold vacuum either. The Haynes manual says the only test is to substitute and run the car. Seems they'd mention vacuum testing if that were valid. Can someone illuminate this for me?

PS: Remember on my FI 142, 25 years ago, when the pressure sensor diaphragm ruptured (high pressure washing was the likely culprit) I repaired it using Saran Wrap and Pliobond adhesive. Ran for years.