Hello...'87 n/a here

Anyway, my idle adjust screw does nothing. I can turn it either way till im blue in the face and the idle will barely change (if it changes at all). What can cause this? I'm leaning towards a vac leak somewhere, but i just managed to put my TB back on and all the hoses seemed in good shape.

As it stands right now the car holds an idle pretty well, it does the surging thing...but after its warm it has a nice solid idle. The issue is that it idles at 1500 rpm and wont go any lower. I've adjusted the TPS...and even replaced it.

Its probably a vac leak but i'd just like to know if anything else would cause my idle adjust screw to be so ineffective. I've already bought the UIM gaskets so i'm ready to do that...and i've just re-grounded the engine but haven't tested it out as of yet so i dont know if thats going to have any effect.

I'm welcoming all kinds of theoretical answers as well as any background information. I'd really like to pick everyones brain...so even general comments about idle and anything related are welcome.

Thanks.

 

It could be an internal leak - like the BAC not seating.

If you can' find the vac leak:

 

What does that screw do?

Nice clean engine BTW

 

Silly question, but did you jumper the initial set plug? It's the small green two prong plug next to the leading coil on the driver's side of the car. Moving the screw won't do anything unless the plug is jumpered.