OK, this is odd....

The CTS and the IAT sensor both tested out bad, and need to be replaced. They are the same sensor, but they are NOT the same connector. Here is a pic of the more common one, corresponding with the CTS.



Notice the offset sliders on the sides. These are reversed from the other one. 

Has anyone replaced the IAT? Where did you get it, did you have connector troubles?

Or maybe I will just file off the little offending tabs....... 
Oddly enough, I was mistaken about the sensors..... OK so thats not so unusual 

I just bought 2 new sensors at AZ, $15 each, and got them home, checked the resistance and they were just the same as the ones I have... about 1.7 cold. 

So that wasn't the problem.

I don't get the check engine light anymore, but the radiator fan never switches on. It will come on as soon as I unplug the CTS. Also it *seems* a little rough starting, which is why I suspected the IAT (I also got a Code 23, which is IAT). Maybe I'm imagining it, I dunno.

Any ideas?

Someone said: test do not guess. So I tested the IAT and the MAP. The IAT is waaay out of specs. It is reading 1.5 Ohms, which on this chart means 230 F incoming air.....  The MAP sensor is easy to test. Provided that you have a DVOM and a hand vacuum pump. This may have been covered elsewhere, but here it is anyway: there are three wires to the MAP. One is 5v in, one is sensor output, and the other is ground. Having identified these, back probe the center wire (the sensor output) and plug it back in. You should read about 3.5v.   Apply vaccuum to the line slowly, and watch the voltage go down.   In my case, it didn't go down at all- the hose was plugged up.  Now it seems to be running fine, as you can hear in this clip:

OK, I have reinstalled the head, and I think I have all the wires back together...the check engine light is on.  When I step on the gas hard, the engine dies/ starved of fuel. On an old carb, this would be caused by the accelerator pump not squirting. So, what causes this on a fuel injection system? Probably I missed some little wire or something.  The exhaust is really loud.....