What causes my car to vibrate?

Most common is failed ineer cv joints. Have them checked to verify.

Axles are about 80 new and 1.5 hours per side to replace

Roy

Cracked no, broken, yes. Did you have the inner cv joints checked as I suggested?

Roy

Symptom indicates possible EGR fault. Is the vibration vehicle speed or engine rpm related?

Check the EGR system.

This engine does not use any balance shaft.

The upper engine mount is just a torque rod for preventing the engine from twisting too much when torsional force is applied.

The engine mounts below and the transmission mounts are the ones to cause vibrations.

Any vibrations due to bad engine mounts ( unless they are completely destroyed) would not be felt during driving.

If the vibrations are more pronounced during slight acceleration, Roy had it correct. The CV inner joints are bad.

Check the inner CV joints for excessive side play and broken boots. Tell tale signs would be grease splashed all over surrounding areas.

If the vibrations also occurs while coasting in neutral at the speed that vibrations occurs, you need to have the wheels checked. They requires balancing.

That is more likely to be engine performance related and most common cause is the EGR system.

Is the MIL indicating and have you checked for trouble codes?

https://www.2carpros.com/articles/toyota-trouble-code-definitions-and-code-gathering-method-1990-1995

Above link explains how to check for trouble codes. When the MIL goes off after engine starts, it usually means no trouble codes for for earlier models, some codes do not trigger the MIL so there is no harm trying.

Btw is your engine 4 or 6 cylinder? I would still suspect the EGR to be the cause. TRy removong the EGR to check if the passages are clogged. The MIL would only indicate if the circuit is faulty but if it is clogged, it might not show.

Give the EGR a check. After so many years and the mileage, the passages are due for cleaning anyway.

You're welcome.

Vibrations more pronounced during acceleration 90% of the time are inner cv joints bad mounts will cause the inner joints to wear. Thic can be hard to see. With the car on a lift jack the left side of the engine so it sits like its excel orating. Spin the front wheels and feel for binding.

Yes, it would because you are running with misfires and you need to accelerate more to get the power desired.