1995 Toyota Corolla Engine Missing Sporadically

My 1995 Toyota Corolla DX with 180,000 miles is missing. It was missing intermittently, especially when idling and cold, and especially when I drove short distances to run errands and then restarted it. It got to the point where it was missing even when warm, and would stall out when idling (always restarted eventually). I took it in to a shop, and they replaced the spark plugs, spark plug wires, ignition coil (which was fried) and the distributor cap and rotor. All of the low speed and idling problems are solved. However, it now misses intermittently when I drive on the highway, only when giving the car gas at speeds of 45 mph or higher. It doesn’t miss when I am coasting, regardless of speed, and doesn’t miss at all under 45 mph. Any advice? This car drives too well under 45 to be headed to the scrap yard yet.

This is pre OBDII which means the oxygen sensor is not monitored. There should be a test port for it somewhere that you stick the leads of a voltmeter into to see if the O2 output is sweeping on the 0-1 volt scale.