De-pinning tools are low cost and many to choose from via eBay, but the last ones I bought came in direct from China and would take a couple weeks to receive, but...they won't help re-size female side contacts, only help release the contact from the connector, so...
Just clean the pins, then spray with
CDC electronic contact spray, don't coat them with anything else
(the clamping force on the female contact is too low; di-electric manufs. don't recommend using it on low pressure contacts)...I've gotten out of the habit and just use
CDC contact spray now.
Gently burnish as best you can, then do the same on the terminal/male side, then apply di-electric grease on the connector shell halves where they mate as a seal. On the female side, just squeeze it down against a small diameter object, like a toothpick, so you don’t inadvertently crush it. Best solve when the contact is too far gone is to replace the wire end with a new contact.
Did you open the harness side connector near the relays on the pass. side firewall, inside the engine bay, where the top left side engine harness connects to the body harness that leads to the PCM?
Those are prone to corrosion and can inhibit signals/ref/return. I’d expect corrosion to raise resistance/lower volts, and a loose pin/contact, if clean, to cause an intermittent path, not necessarily high resistance. In other words i’d blame corrosion, first, and more likely, as opposed to a faulty connection, where there would be 0 resistance because of a break in the path. Not sure a loose pin would raise resistance….?