Thanks for all your responses! Turns out it was the crankshaft pulley with a worn harmonic balancer/rubber sleeve. Got a salvaged one for $65 and everything works well.

I know this was covered in earlier posts but I figured I would share how I removed the crankshaft bolt on my '94 V6.
Removing the crankshaft nut was really easy using an 18" breaker bar and 24mm deep impact socket. Here's what I did in case anybody else is removing the bolt for the timing belt or seal replacement.

1. Remove the air filter box
2. ...upper fan shroud
3. ...cooling fan and clutch assembly
3. ...power steering, A/C and alternator belts
4. cover the rear of the radiator with a plywood board (21-3/4 X 14" to avoid damage while removing the crankshaft bolt
5. put the 24mm deep socket on an 18" breaker bar and line up the bolt, socket and bar so it rest on the DRIVER'S SIDE wheel well.
6. Pack a towel tightly around the front of the breaker bar handle end
7. Pack a towel tightly in between the socket/breaker bar and board covering the rear of the radiator (keeps the breaker bar snug)
8. Unplug the ignition coil plugs (on my '94 there are 3 plugs on top of the engine at the ignition coils. (prevents engine from starting)
9. Review what you just did and make sure the breaker bar is sitting snugly on the driver's side of the engine on the wheel well.
10. Turn the engine over for a quick bump to break the bolt loose. Should come off easily!
11. Smack the crankshaft pulley with a rubber mallet to loosen. Pulley should jiggle and slide out.

To install, use a pulley removal wrench to hold the pulley and tighten the bolt to 123Ft/Lbs. (got mine from Harbor Freight & Tools, item# p-45407 $8.99)

Thanks again and best of luck if you have to remove the pulley bolt.

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