May sound like an easy question, but can someone tell me the correct way to check engine vacuum on my 98 355F1? I assume I should remove the vac hose from the base of the rear most throttle body on each bank and take a reading from that point, leaving the check valve in line and place. I assume the vacuum pump that provides brake assist will not matter in this case? How many inches of vacuum should be acceptable as normal? Thanks
Very interesting, I just went throught the same ordeal, I'd be interested in answer. My showed 4 to 5 inches where you're talking about, 97 F355 GTS 80k miles.
Mine read about 5 inches as well. Seems way too low. I was expecting anywhere from 18 to 20 inches at idle, about 1050 rpm or so.
Yes it does oscillate, most likely due to intake pulses, mine is reading slightly higher, between 5 and 6 inches. I just found your other thread and am trying to follow along.
There really is no engine vacuum in the F355. Each cyclinder has its own individual vacuum. Brake assist is provided by a hydraulic system up under in the front left bonnet. My engine looks to run around 15-17 in-Hg in a fuzzy image I took years ago with manometers on each throttle body.
