Looks like a simple check valve, allows vacuum to flow only one way. Try checker or auto zone or a place like that.
95' Jeep Grand Cherokee Laredo, 148k, 5.2, NP242, 46RH, 4" RC lift, all new adjustable ca's(2 IRO front uppers and the rest RC adjustables), nitro shocks, JKS TB's, Jet Chip, Dynamax cat back, Magnaflow cat, GTP hood vents. 31" Pro Comps with Rock Krawler "D"s. Westin brush/grill guard with Hella 500s, 411's, Solid diff covers, detroit locker rear, power lock in front, SYE and Tom Wood's front/rear shafts, RE discos, BPE's, d-rings front and back, factory tc and rad skid, hitch, Sliders next.
03' Jeep Grand Cherokee Laredo, (wifes Jeep) 99k, 4.7 5 speed auto, K&N, KYB shocks, drilled-slotted rotors, All the toys.
2000' Ford Superduty, F250, 7.3, 198K, 37's, too much to list.
I stopped at the Jeep dealership this morning and found out its hooked to and part of the Duty Cycle Evap Purge Valve PCM Output. How did I find this out you ask? They sure didn't know. They couldn't find the valve in their parts books either. Even better the Chrysler Rep was there and he had no idea what it was or where to find it. I asked to look at their book and I found what I just told you about it. Not much info on it. Reason I asked is thats the only thing missing after I changed Engines and thought maybe it had something to do with my idle surging from 400 to 1400 and back and forth.
Hell, I've tried everything else.
__________________ 2013 Dodge Ram 1500 Express Quad Cab. 5.7L Hemi 6 speed automatic 3:55 gears LSD with 20 inch rubber 2000 Jeep Grand Cherokee Limited 4.0L 2003 Nissan 350Z Enthusiast Model 6 speed manual 2002 Audi A6 Avant Quattro 3.0L Auto
Back in the day I had a Honda that did that after I worked on the cooling system. I didn't completely bleed out all the air causing to idle like you mentioned. Don't know if the V8 Jeeps have this trait. I did my 4.0's system in the winter and there was no bleed valve to be found.