Sometimes it's the simplest of things, your driveline "vibration" sounds just like the "shop truck" I bought off a bunch of ASE Certified mechanics who did an engine swap/torque converter swap and could never figure out the cause of the slight driveline vibration, so they "dumped" the truck on me, after 5 minutes of ownership, it was "cured"....firing order, 2 cylinders crossed wires, 4 ASE mechanics and a month of on and off troubleshooting, they over looked the obvious....so rule out the simple things before you go tearing stuff apart
Deffenitley, that's why I'm going to rule out ignition first.
In almost wondering if it's a bad plug wire or if it's my ignition coil.
The coil in running was in a truck that had caught on fire.
My dad had a 75 w100 and the wiring at the amperage gauge caught on fire and that's what burned down the cab.
They got the fire put out before it damaged the engine and under the hood.
But I'm wondering if maybe that coil got hot in that fire and it works but not exactly like it's supposed too.
I'm not sure if a single coil system like mine can affect an individual cylinder or two, but the last time I had my spark plugs out cylinder 7 and cylinder 8's spark plug were questionable.
Not fouled but looked like they weren't firing as well as the other plugs were.
Could a coil cause something like that to happen if it's on it way out?
Something is telling me to try a new coil just because of what I seen with number 7 and number 8 plugs and the fact that the coil I'm running was on a truck where the cab burned down.
The ignition in running is a crane cams hi-6 cd ignition box with the crane cams lx91 e-core coil. I measured the coils resistance and didn't see anything that jumped out at me really.
I guess you could say the secondary resistance of the coil was a little low at 4800 and the primary resistance was .07-1.0 which is ok.
I've been trying to find online what my specific coils resistance should measure out at.
Plug wires are Taylor thundervolt 8.2mn, they are only a couple years old but some of the boots are torn from taking them on and off as much as I have over the years.
Maybe this issue is ignition, it's just strange how it runs so smooth untill 2500 rpm and then all hell breaks loose with the vibrations.
I thought it was drivetrain related for the longest time, but being that it's strictly rpm dependent I've changed my mind.
That and I'm running a 500 dollar 1350 series cv shaft with all spicer yokes and u-joints and my pinion is 1-2 degrees below inline with the shaft which is exactly where you want it to be with a cv shaft.
All U-joints are tight, and output shaft bearing on t-case is tight.
