Colin..please back up and reread what I wrote. According to the way our pcm controls things on the engine it'* the ground that is being toggled to operate the soleniods. I'm pretty sure this applies to 97 the same way it is done in 98, although I don't have the FSM'* for 97 anymore.

Wouldn't a bad connection to ground cause issues with toggling them, similar to how a corroded positive cable causes voltage delivery issues?

Yes, only if he had fixed the connection from ground to pcm. It sounds like he cut the connection to the pcm from the soleniods and wired them direct to ground.

That'* what I did. I've since run them back to the PCM. I had DTCs for both circuit faults....

And my grounds under the hood are 4ga to the shock tower and 4ga to the block where the alternator bracket attaches, and 8ga to the stock fender location, and 8ga to the headlight grounds on the driver side. When I re-did it I picked up power for sure. I ground down all the connections a little to strip the paint\debris and then applied dielectric...

And does the PCM have a main ground? Where is it exactly?

For what it'* worth, the Haynes manual says there are four ground wires coming from the PCM, all next or close to each other; two should be tan/white, and two should be black/white. It doesn't say where they go, but they all go together. Not a definite answer, but hopefully it helps.

One main ground as I mentioned on BPro, if you remove the passenger tire and splash shield it'* in on the block just past the oil filter adapter. That then leads up to the main ground splice that'* halfway between the alternator and EGR valve in teh wiring loom over the rear valve cover. You can't miss that splice when you begin digging in that loom. It'* got a ton of wires going to it.

Okay. Final Update bump. Lemme sum this up real quick for ya.

Got all the wiring to the PCM handled. Redid PCM ground. Solenoid harness showed correct voltage in both open and closed operation with Tech2.

Purge solenoid turned out to be shot. Fixed that. Still EVAP leak somewhere and accompanying vacuum leak. I was very irritated.

It'* the connection at the tank. I was fed up with this EVAP bullcrap.

Two words... EVAP Delete.

New vacuum setup...AN fittings... Had to custom fab one till I pick up the right one

Nice EVAP delete. Now you can remove the canister and have a great place for a custom air intake.

Downside is it would cause codes to pop up again. Fortunately he has a method for deleting the codes from the pcm.

Do what I did, no report. Problem solved.