1993 Mercury Topaz runs bad when cold and intermittently wh

First of all, I thank you for your detailed description of your symtoms and the components you have checked. I wish others were as complete. It would save a lot of dialog back and forth. Anyway, on to your problem. If your system had a crankshaft position sensor, I would say to change it, but it doesn't. From your description it sounds like a lean condition when the engine is cold and also causing the power loss when cruising. You've pretty much ruled out a fuel loss, so my next culprit would be the intake air temp sensor. All of these I've ever seen go bad I can count one hand. But, if the IAC is telling the ECM the air is warmer than it is, it's going to send a lean mixture and this signal could be intermitent. I live in Minnesota, so I'm quite familiar with cold weather problems. We can test this theory if you can plug in a mobile diagnostic unit of a type and watch what air input #s are versus what actual air temp really is. Let me know what your thoughts are on this.

Even in open loop, the ECM uses information from the IAC and the coolant temp sensor (CTS). Which brings me to a question. When you first start the car, does the engine rpms go up on fast idle until it warms up, or does it stay at low idle? Also, tapping on the mass air will usually show a problem on a GM unit, but necessarily on a Ford. Let me know on the idle. In the interum, I'm going to check a couple of other sources. It's been a busy day.

Well, from your description, it's one of two things. If you had a "crankshaft position sensor" (CPS), I would say that was your problem. But, you don't. Without any ECM codes we can only make an educated guess.
Mass air: If this were not sending input to the ECM until it goes into closed loop or was intermitent, this could cause the problems you're having. BUT, the ECM should pick this up and register a trouble code.
ECM: I'm not one to jump in and condemn the computer first off. But it looks the ECM isn't accepting fuel control inputs until it goes into closed loop and then intermitently drops back into open loop. When you pull over and shut the car off for a few minuets, the ECM resets and away you go again. The choice is yours. Personally, I'd look at the computer. Let me know