85 300SD w/ Trap Oxidizer vacuum presure reading

I followed Kent's instructions the best I could in his Vacuum Diagnostic manual. Here is what I did and what readings I got: following the main black plastic line to the firewall, there are several lines that split off. 5 in total, I believe. I unplugged the four smaller, colored lines and plugged them with golf tees. The remaining line is actually some sort of plastic housing unit with a curved rubber hose attached. I took my measurements from this point and with the engine on, I got a measurement of 10 psi from my mityvac. I think this means something is up with my vacuum pump, unless I performed my measurements incorrectly.

Did I do the vacuum pump test correctly? The instructions are for the older models w/o trap oxidizer and so the descriptions are disorienting when looking at my car.

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