no, I noticed that when I pushed in on the clutch (all the way, to put it in gear) the surging stopped. So, to see how far the clutch had to be pressed for it to stop I played around with it, and it only takes the clutch being depressed about 1/4 of an inch for it to stop.
Also, its not so much of a surge (up) in RPM, as a RPM drop. I know where the CTS is for the gauge, where is the one for the ECU?
The one for the gauge is called a sending unit, and has a single, small wire going to it. The wire "plugs" into a threaded 'stud" sticking up from the sending unit. The one for the ECU is called a sensor, and it has 2 wires, and "normal" underhood "locking" type plug. It is located in the intake manifold, just above the thermostat housing, on the drivers side. It's basically right across from the sending unit. A 1" combination wrench should be the right tool to get it out. You'll want to remove the air intake tube first though (from the air cleaner to the throttle body). Also, remember that there is coolant under that sensor. If the system is full, you'll have a pretty good size spill. I would drain a little bit out, through the radiator drain plug first. Also remember to use a little teflon tape on the threads.
All that said, I wouldn't just replace it, without testing. If you have access to a scanner (not just a code reader, you need live sensor data), you can do it yourself. Let it sit overnight ("cold soak" is the term). Before you start it up, hook up the scanner, and look at the readings for both the coolant temp sensor (ECT), as well as the inlet air temp sensor (IAT)(looks like the coolant sensor, but it is screwed into the upper intake manifold, on the driver's side) If either one of these reads much different then ambient air temp, then replace it. Also, start up the truck, and monitor both of these sensor readings as the truck warms up. Keep a close eye on them, and make sure that they increase smoothly and steadily as the truck warms up.
Also, I still wouldn't rule out the IAC, just because you cleaned it. Fords are notorious for IAC valves causing idle issues. Next time it is in the middle of one of these idle drop issues, unplug the IAC w/ the engine running. If the idle changes and smooths out, then there is your problem.
You could also have a bad MAFS (MAS), despite your cleaning. Just because a sensor isn't throwing a code, doesn't mean it's working right. Especially on OBD1, unless a sensor gets WAY out of range, the computer will just see that the sensor is still sending a signal, and assume that the data is correct; when it fact, it may be very wrong. For example, let's say your ECT sensor reads 195deg when you first start it up and the engine temp is really only 50deg. Well, as far as the computer is concerned, 195deg IS a valid reading that occurs during normal engine operations. The reading is within the normal range it would expect to see from the sensor, so it doesn't set a code. It accepts the 195deg as the engine temp, and acts accordingly. For one, it would command less fuel, when in fact the engine is still cold, and needs cold start fuel enrichment to run properly. Now, on the other hand, if the sensor was sending a reading of 295deg, then the computer would likely set a code, because it "knows" this is outside the normal range.
If you don't have access to a scanner, I think this is a case for taking it to a mechanic w/ the proper equipment to diagnose it.