Perhaps you already have discovered this, but for other new owners, maybe this info will be useful. So, I apologize if this is redundant for you!
You can easily check the fuel pumps current draw via the diagnostic (testing) connector protruding from the (large) wire loom near the windshield wiper motor (see photo of the red wire and connector)
By configuring a VOM to read amperes, you can connect the VOM in series between that test connector and the POSITIVE battery terminal.
Each pump draws between 4-5 amperes each for a total of 8-10 if both are working properly.
This
diagnostic test is conducted with the
ignition switch in the OFF position
NOTE: As you have indicated, to determine which pump is or is not working up to expectations, by pulling the fuel pump fuse (located on the side fuse panel - accessible by opening the passenger side door) by elimination and observing the amperage draw you can determine individual performance.
For a dynamic test, taping a fuel pressure gauge to the windshield and going for a drive will confirm whether or not fuel delivery is an issue. My 1990 fuel pressure when cruising in normal mode is 44-45 PSI (~45 PSI or 310 KPa) and at Wide Open Throttle (WOT) pressure jumps to 55 PSI (~379 KPa).
One other thing that gets overlooked is the accordion bridge hose between the air filter box and the plenum intake horn. As they age, they sometimes will collapse at full throttle, thus pinching off the air flow...AND it occurs beginning right about 4000 rpm! It is an easy fix tho.
- Marc supplies some wire loops that fit inside of that hose to keep it from collapsing.
- Or, (as I did) you can construct a sleeve and insert it inside of the hose. (I used aluminum sheet metal and pop-rivets to fabricate mine. Inexpensive, invisible from the outside, and works great!)
- OR, you can install one of the smooth custom hoses (from Jerry's Gaskets) which work nicely and look very nice.
Removal of the vacuum pump suggests the secondaries are eliminated either entirely including the actuators and associated plumbing and the throttle plates (SPTs), OR as some do - just zip-tie the SPTs open and leave the plumbing in case one wants to revert back to stock later. And, that said, if the secondaries are removed or tied open, then the FULL ENGINE POWER indicator on the dash should be illuminated and the manual switch should be permanently in the FULL position (1990s only. 1991+ have a momentary toggle switch (key) that illuminates a green light when in FULL POWER mode - and must ALWAYS be illuminated if the secondaries have been deleted [mod])