Yes, 87-88 Fuel "overflow" tank is in right rear ¼ panel in front of wheel well.
No air flow likely mean lines to it are block somewhere.
I'm not sure if one tube into the tank has a "metering" hole that's way smaller then tube connected to it.
If there, The small opening maybe block w/ rust.
Older main fuel tanks has this on vent line in the tank. Not sure if is true for 87-88 main tanks or if move to overflow. If is in overflow then likely in the output to the EVAP canister.
Even w/o tube blocked, small hole can seem blocked because of limited flow.
Small hole is there to prevent Liquid fuel getting to EVAP canister because Liquid Fuel will kill them.
Try using a hand pump w/ gauge to pressure 2-4 pounds and see if pressure drops like tire w/ small leak.
Maybe could try w/ hand vac pump w/ gauge but don't try to pull biggest vacuum you can make.
If you try either, leave 1 tube open to air first. Then repeat tube sealed. Second test is to make sure overflow tank doesn't have rust holes starting to leak too.
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