Cheer up, calm down, you are in good hands here. It is NOT the timing belt.

The timing belt, when it was going OK and then fails, is a go/no go situation. No mid-ground. Engine runs or not. If not, no internal damage from that. (Running rough right after a T-belt change can mean a tooth-off installation.)

The other answers have the right idea. Something that causes one or two cylinders to mis-fire. Fuel system or fouled plugs. When one cylinder quits, BTDT, the loss makes the engine unbalanced and it will shake like a toy in a dog's mouth. It also has 25% less power.

If you have not changed the spark plugs, it would me a good idea. Gives you a chance to inspect the old ones for clues. Get a set of Bosch WR 7 DC and gap them at .028 inches. Use a dab of Anti-Sieze on the threads, and a torque wrench. If the budget will hack it, get a set of Bougicord ignition wires, and a new Bosch Cap and rotor.

Make the ignition system no longer a suspect.

Keep on trucking rolling, you will yet be able to drive it over to wave at the seller.

Good Luck,

Bob

:>)