A ton of people have posted about high idle, the MPS tuning and other things related to air leaks that cause a high idle.  

 

A few notes about that.

▪Read the posts about the high idle and air leaks.  You need to go over everything

▪I had the throttle body rebuilt by a machinist that posts on 914.com to eliminate a bad throttle body butterfly shaft leak

▪I replaced all injector seals and the intake runner boots

▪I replaced the Oil (OEL) filler cork gasket.

▪I replaced the cold start injector gasket

▪I replaced the throttle body gasket

▪I zip-tied the MPS and decel valve hoses

▪I zip-tied the PCV hose at the PCV

▪I zip-tied the distributor canister hose

▪I resealed the PCV  at the Oil filler

▪I did a vacuum test on the MPS

▪I did a vacuum test on the cold start hoses at the two far-ends.

▪I resealed the air intake temperature sensor

▪I tested the cold start valve for electrical function.  Note that they do vacuum leak a small amount when closed, it is hose leaks that I was concerned with.

▪I removed the air distribution box and checked for leaks.  I even taped it shut and did a vacuum test on it.  I shined light through it in a darkened room, etc.

 

And then, I found a crack in the F-connector where the MPS and Overrun come into the bottom of the air-box (the vacuum chamber lower part).  It was in-between the two hose fittings on that F-connector.  This is the 914Rubber.com part.  I am not happy with how flexible this replacement part is (silicone and not as stiff as the original) and those anodized tubes are loose fitting, requiring silicone sealant or zip-ties.  But once that was sorted, the air leak was gone.

 

The crack was in the area below the top plug and bottom plug, between the two horizontal protrusions of the "F".