You are fine checking the voltage on coils, but you do need a oscilloscope and know how to read the patterns, so to a unskilled person it is a bit of a no go. You measure the voltage on the primary side and this will show you what the secondary side of the coil is doing, don't worry about dying, there isn't enough current to kill you, 30k volts does bite but that is all.
Where do you feel the vibration, through the floor, steering, just a noise?
Inner CV axle joints can do this when they start to wear, also blocked exhaust can cause a vibration noise under these circumstances. It would help to explain the vibration more? As this would give a clue to what it is.
So I think I have a few things going on here. First I have a leak on one of the spark plugs gasket due to a bad valve cover job. So I need to get that fixed. Then address this coil issue. I think I need new one or more, but not 100 sure this is my issue.
The vibration occurs throughout the entire car under heavy acceleration. It shakes the rear view mirror and you feel it though the chassis. You don't feel it through the steering wheel like a shimmy. The vibration is more noticable at lower speeds and dissipates as you reach highway speeds. If you accelerate under light to moderate it's not noticable and can be avoided if you drive like a sane person. I believe it's more evident when making left hand turns under acceleration, but is also there on straight aways and right hand turns. I noticed the other day under very hard left hand turning at higher speed I feel a vibration, but I don't feel comfortable trying to replicate that situation.
So to recap
Vibration in chassis, not noticable in brake or acceleration pedal, or steering wheel.
Only under acceleration, more off the line and almost gone by the time highway speeds are hit.
I have done maintenance after I have noticed the issue (not trying to fix this issue, but just maintaining)
Replaced back pads and rotors
Replaced front pads and calipers
Replaced engine mounts (haven't done transmission mount.... Yet)
Replaced valve cover gaskets and spark plugs tube seals (had repair shop do this)
Replaced pcv valve and hose (should have done this sooner, love the smooth idle)
Replaced rear sway bar bushings
Added new negative terminal and ground wires for battery and engine
Greased drive shaft and u joints
None of that work effected this vibration in any way.
On my list are differential bushing( have parts), steering rack bushing (may have to replace due to very minor leak), drive shaft flanges (have parts but just waiting for time), passenger side axel reboot (minor tear but no grease leak yet).
About a year ago I replaced the passenger side inner wheel bearing with AutoZone aftermarket (didn't know I would need one and didn't have time to order timken) before HIH7 I checked bearing wheel nut torque, was loose, adjusted to spec.
Sorry for so much info. Just not sure what's relevant and what's not.
