1) If you have some scrapyards searcher near, the coolant sensor is one piece with the tank. You must change the two but it's not very hard. You can find it on others SLO (normal taurus and sables, 96 to 2001 maybe later). It's easy to know if you find one because you see a small electrical wiring going on the right bottom of the tank witout dissembling it. If you're very lucky, you will find one with a clear top and a sensor, they are more reliable. The ones with a black top tend to develop a big crack on the bottom and progressively lost coolant with pressure building in it. I had this prob on my SLO at around 130 k. I searched some days before I found it was not a blowed head gasket...
2) If you don't want to pay for a new the IAC valve, this part was in use on some others Fords... Mostly on 2.5 V6 Duratech (Contour, Cougar, Mystique, etc. for the same period). It's a 2 bolts job but IAC is harder to unbolt on these motors than ours because they are on the upper rear intake. Be sure to have the good tools because the bolts are soften hard sticked on intake and the head will strip. If you found a good 2.5, I suggest you to take the crank pulley, it's the same than our. I say that because mine was rusted like **** and I had to redrill the holes to retreive it from motor to change the crank seal.
Don't forget that the more you are asking to the car, the more parts will fall apart. You will "wake up" all weakers and/or aging parts.
Good luck,
