High idle 2.0 djet, Been working on it for a little Options

[Brasil914]

Hey all my name is John. I have been using 914 as a resource for a while but just registered (I have questions). So I have a 73 2.0 hand me down from dad. And I have idle issues. History: 86 dad snapped spark plug. Got what he could out of it and then tried to vacuum the head thru the spark hole. Was worried that not every thing was out so never started it again, and forgot to drain the tank. It sat in garage and storage until 2008 when he gave it to me. First thing I did was run a borescope in the cylinder , couldn't see jack. So dropped the motor pulled the head and the cylinder was clean as a whistle. Did some work over about three years sourcing parts and such. And got it to run in 2010. Then moved to SC. Got it here six months later and started on it some more. No I have had down time from work and have started tinkering again after 2 years. I have replaced all hoses,injectors and seals, yesterday I opened and freed up the aar. All this I and I have gotten the idle down from 4K to just under 2k. I can get it down to about 1100 but I have to remove the hose from the MPS? ( the Can on the right wall). The second I get the hose near or on the nipple the engine throttles up th 2 k. And runs smoother. At 1100 it sounds rich a lot of back firing. ( exhaust ignition). Any ideas gents?