The problem of my engine running a little rough and stumbling a bit seems to have gotten worse. Above 2000 rpms, engine runs very roughly. With the hood open, truck out of gear, and tugging on the throttle, the engine was shaking quite a bit. Is this the problem of a loose motor mount or something? Hopefully not a big deal but I'm worried that it will become even worse. Thanks for yalls help!

1991 22re PU, 4x4, 184k mi.

PS Plugs, wires, rotor, cap are pretty new. I'm already running Rislone in the engine and seafoam in the tank.