Had the strangest problem with my civic for a while. Its a 94 with a 1st gen b16 converted to OBD1. The problem is not while I'm stopped but more so while I'm moving or coming to a stop, mostly when i hit bumps. Coasting downhill and hitting bumps the idle will jump to 1500 or 2000, fall then go right back up again. If I'm in gear and it happens it feels like the car jerks forward even though I've kept the the same amount of pressure on the gas pedal. Living in a city with shitty roads this gets annoying and ruins my MPG's.
Ive searched for vacuum leaks with carb cleaner and propane but i don't believe there is one. I've purchased new ground wires and battery terminals and the battery is not even a year old yet. I'm going to try a new air filter but from there I'm out of ideas. When i had my valve cover open i noticed most of my lost motion assembly's stuck. Would that have to do with anything? I've also done a valve adjustment already.
Any help would be great.
Also noticed this
That nipple has a cover over it and when i remove it the idle moves up a bit then settle back down. Not sure but I would think that it should be connected to something. Any ideas where it goes to.