replace ECM

You will never find the problem by throwing parts at it. From your description, it's not the EEC-IV & it would be the last thing to try, not the first thing. BTW, Fox bodies have no crank position sensor; pvc is plastic pipe, pcv is positive crankcase ventilation.

Problems that occur when cold but go away when the engine warms up may be related to the ECT (Engine Coolant Temperature) sensor. It lives in the front passenger side of the lower intake manifold. Normal location is in the two tubes that supply coolant th the heater.

Here's the test data, your results should be similar...

Dumping the codes will normally show a faulty sensor. The ACT & ECT may be on the outer limits and not set a code but cause problems. Use a DVM or multimeter to check them.

Pin 25 ACT signal in. at 50 degrees F it should be 3.5 volts. It is a good number if the ACT is mounted in the inlet airbox. If it is mounted in the lower intake manifold, the voltage readings will be lower because of the heat transfer.

Pin 7 ECT signal in. at 176 degrees F it should be .80 volts

The ACT & ECT have the same thermistor, so the table values are the same.

Here's the table: The values are +/- 15%, so don't get worried if your readings vary a little bit.

Voltages are measured across the two connector pins of the sensor with the sensor connected. Some safety pins used to probe the connector from the rear will be helpful

50 degrees F = 3.52 v
68 degrees F = 3.02 v
86 degrees F = 2.62 v
104 degrees F = 2.16 v
122 degrees F = 1.72 v
140 degrees F = 1.35 v
158 degrees F = 1.04 v
176 degrees F = .80 v
194 degrees F = .61
212 degrees F = .47 v
230 degrees F = .36 v
248 degrees F = .28 v

Ohms measures at the computer with the computer disconnected, or at the sensor with the sensor wiring disconnected.
50 degrees F = 58.75 K ohms
68 degrees F = 37.30 K ohms
86 degrees F = 27.27 K ohms
104 degrees F = 16.15 K ohms
122 degrees F = 10.97 K ohms
140 degrees F = 7.60 K ohms
158 degrees F = 5.37 K ohms
176 degrees F = 3.84 K ohms
194 degrees F = 2.80 K ohms
212 degrees F = 2.07 K ohms
230 degrees F = 1.55 K ohms
248 degrees F = 1.18 k ohms

First question - is the check engine light lit?
Second question - cold air intake or stock airbox?

Check for vacuum leaks.

Your posts are very hard to read.