A-3 4-4-3 ABS Pump motor, electrical or mechanical fault
A-6 2-1-4 Engine speed (RPM) sensor signal missing sporadically

If the ABS light refuses to turn off after 20mph, check the electrical wiring. The ABS pump motor never fails mechanically.

Your best bet to poor running is the RPM sensor. I would check the wiring for the cam position sensor. Make sure it does not get close to any spark plug wires or the coil wire. Also check the connector for those 2 wires, plastic tends to degrade over the years.

The PCV has nothing to do with engine performance. First, clean out the flame trap, located next to the throttle body. If there is still a plastic screen in there, throw it in the garbage - there has NEVER been a backfire through the flame trap.

The problem with a clogged oil separator is that as the crank pressure increases, so does the likelihood of a seal (cam or RMS) being blown out. In order to replace the oil separator you must remove the intake manifold. Long job, lots of bending over, and for the 1993, hard to find parts. Normally, the oil separator doesn't get clogged, but the passages from there back into the block do get clogged. Also the hoses tend to get very brittle from the heat.

I believe your car has EGR, which makes it more interesting getting the manifold off.
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Keeping it running is better than buying new