s4 na wont idle correctly
 

Alright so I have a 87 na that recently just got a engine swap from an 86 donor. Were not sure where some of the vacuum lines go and is what I suspect some of our problems are. At first the engine would rev to 4000 rpm and idle there. We adjusted the plates using a screw that is located on the same side of the throttle body that the throttle cable is on. I also tried using another small screw that has a nut on it that is towards the top and on the front side of the throttle body. As of now the car will idle but it will surge around 1000-1500 rpm. I think this is due to me over adjusting the littler screw with the nut on it towards the front. I have some pictures and if anyone has any knowledge of vacuum lines or anything else it would be greatly appreciated. thanks.

first picture shows 3 ports between the manifold and the fire wall. The one closest to the driver is capped. the other two and just connected by a single hose

next picture shows the little screw with the nut on it that i was talking about

third picture shows a port that is down by the exhaust manifold. were not sure where this one goes. or any for that matter. and another port that is higher up. to the left in this case. looks like its a bigger port than the others.

Since you have some vacuum ports looped together and some capped off I would get a vacuum diagram from the 2nd gen archives and especially check the solenoid rack for proper connections. Someone may have removed some emissions stuff. You may be ok but you'll never know until you trace everything down which means removing the UIM to get to the solenoid rack. Not that such would cause a 4000 rpm idle but there could be some further leaks.

Pic three the cut hose could be coming from a hard air pipe that goes to the converter air supply but also supplies air to operate the 3rd port actuators. Just trace it down. If that is it it won't affect your idle. It looks like you are missing the port actuator in that pic.

The screw within the nut affects the secondary plates. If you were to loosen the screw and the lever which rests upon it moves upward then the lever was adjusted to the wrong position. The lever should not be pressed down any at all and any means any here. If you were to pull the screw off that lever then that is the position the lever should find itself in. Chances are the lever is where it is supposed to be or quite close because once you press that lever down some it will increase the idle by a large margin.

A fluctuation could be TPS related but it can also be vacuum related. As suggested, find the diagram and follow it implicitly. There should not be any hoses leading to nowhere or nipples exposed to atmosphere.

Yea im not convinced that the engine wasnt gone. Were doing a v8 swap on her now and will post pictures when its done

based on what?