Engine vibration after timing belt replacement

1994 dodge caravan 3.0, 6 cylinder. Mileage :105,000. I was losing antifreez slowly, the mechanic said either the water pump or something arround the water pump is leaking.

I agreed to replace the water pump along with the timing belt.
After the replacements, the engine vibrates on idle, more vibration when the vihicle is in motion especially on highway speed.
The shop said you need a tuneup, I knew that was not the problem but I allowed them to do a
major tune-up including spark plugs, plug wires, distributor cap, rotor, fuel filter and air filter.

Engine vibration did not stop after that.

They said your problem is engine mount, I had my doubt about that also but I agreed to let them replaced the engine mounts with after-market

ones, that did not stop the vibration either.

Went back to the shop several times with no success.

The shop owner said to drive it arround for a while and bring it back if the engine still vibrates. After over 20,000 miles, still vibrates.

I have no confidence that this particular shop can find the problem and fix it.
I really appreciate your help.