Mystery vibration at 25 mph can't be diagnosed. It's not the front end!

I paid a garage once,to replace a distributor. I could have bought a manual,tools and a good timing light for what i paid. Thats where this mess started. 30,000 plus in tools and i now fix cars for a living. With integrity. Had i not found the problem, you would have paid for plugs and a fair price to change them.
I told a customer if i cant fix his no start escape it would be no charge. Determined to figure it out, i started pulling plugs,wet and had compression and spark.
Plugs were wet-water wet.
Turns out his employee used gas from a boat instead of buying gas. Guess what? Boat doesent run either.figured out the escape and fixed the boat without even touching it. Big load of water.
Spent too many years working around incompetent people,so i took matters into my own hands.

Also turns out i dont play well with others. Guess my kindergarden teacher was right.

Has to be something causing your vibration, im sure you will find it. I'm rootin for ya!!