With the high mileage on your ride, the vibes might be coming from the drivetrain, like the torque converter or the transmission. Check out the transmission mounts too - worn ones can make things shaky, especially when you're putting some load on.

Take a good look at the exhaust system too. Any issues there, like misalignment or worn-out parts, could be causing those extra vibrations, especially when the engine is warming up.

And since your vehicle has been around for a while, it might be a good idea to do a compression test on the engine. That can give you the lowdown on any internal issues that might be causing the vibrations.