Car question

[glatt]

Well, I don't have a vacuum gauge. Maybe I should get one. Seems like a waste of money for a tool I'll only use once. But I wish I had one.

I listened at the exhaust, but don't trust my skill at identifying the sounds I hear. It sounded like an exhaust. Didn't seem abnormal at all.

I'm confident that I eliminated the EGR system as the cause of the problem, and even cleaned the EGR valve, but last night I drove the car to a party in DC (because it's small and easy to park) and it's as bad as it ever was. The problem is still there.

When I watch the engine, one of the radiator hoses is vibrating like crazy. The engine doesn't seem to vibrate much. At times the battery is vibrating a lot too, so you can't read the writing on it, but yesterday it wasn't so bad.

I guess it's back to the drawing board.

Under the section for vibration diagnosis, the shop manual talks a lot about road vibrations, but those don't apply because the problem is only noticed when it's stopped. The only part of the vibration diagnosis that applies is the engine speed sensitive section. They list a bunch of scary sounding possibilities:
-Belt or engine driven accessories like generator, A/C compressor, power steering
-drive belts and their tension
-bad bearings
-bent shafts
-faulty or loose flywheel

For rough idle, which seems to me like it might cause cabin vibrations and loudness, they list the following:
Sensor checks
Check O2 sensors
Check Throttle position Sensor
Check Engine Coolant Sensor
Check MAP sensor (but they don't say how)
Fuel System Checks
Check if condition occurs under Rich or Lean conditions
Check EVAP control system
Check fuel injectors for leakage
Check fuel pressure
Ignition System Checks
Check ignition voltage with spark tester
Check spark plugs for wet, cracks, wear, gap, burned, blistered, dirty
Check spark plug cables for resistence
Check ignition timing
Additional checks
Check for vacuum leaks (I did this)
Check ECM/PCM grounds for clean, tight, routing
Check ECM/PCM with scan tool to look for A/C signal
Check EGR (I did this in the post above)
Check battery cables and ground straps (battery cables look fine)
Check Crankcase Ventilation Valve
Engine Mechanical Check (It's like they are just listing engine parts now)
Motor mounts
valve timing
low compression
bent push rods
worn rocker arms
valve springs
camshaft lobes