need help with code 13 on 90 gxl

[SmokeScream]

just got this car a week ago. havent really drove it as i have been fixing problems here and there. taillights and dashlights didn't work. after putting new connector in headlight plug they came back. idle is a little bouncy when warm. took it out for a quick spin and engine light started to flicker when i was on the throttle. when i got back it didnt want to run unless i gave it gas. pulled codes and got 13 (pressure sensor) and 30 (split air valve). code 30 might be because some previous owner pulled out air pump and 6pi actuators. is the oe vac line for pressure sensor hard plastic? thats whats in my car. i've read there's supposed to be a plastic restrictor pellet in the vac line. someone also said they had that problem with a cold air intake and when it was cold out. any ideas?