The IAT sensor (and called that by then) was not integrated into the MAF until much later. I'm thinking around 2001 but it might have been sooner. I'd have to look at the manuals.
This sensor mod has been done and proven to work on a lot of older trucks. The ECT version is the most effective if you up your octane with it. In practice it works exactly like the "180 degree t-stat" mod where the engine temperature is reduced.
On newer trucks the ECT mod will do a little, but the IAT/ACT mod will do nothing. This is because in later trucks the IAT/ACT (depending on what you want to call it) was taken out of the equation for adjusting timing.
The factory service manual even indicates that the ECT will have an effect on timing.
Lieing to the computer, as it was stated lol, is a time honored and proven method of getting a little extra power on some vehicles, particularly with older computers and sensors. Modern trucks are full closed loop with much tighter controls and checks and are harder to fool into doing anything beneficial.
I tried to do this on my truck and fooled myself into thinking it actually did something. But after talking with some people (and I think Doug from Bamachips was one of the contributors) it came to light that in the new tables in the PCM, the contribution of the IAT to timing was "zero'd out".
However, you can get some benefit from the older ones. You can try it and if you have problems, just take it out. You don't want anything too rich -- but timing advance you can use to get more power across the board.
What I'm not sure of is how much advance you can get. But don't worry too much about the ECT -- only on the later trucks will it make a huge problem because on the OBD-II/EEC-V vehicles the PCM won't get into a full "closed loop" state without the engine temperature coming up to spec.
Unless you introduce an outside voltage INTO the line to the ECT, you can't fry the computer by cutting the wire, so relax on that one. However, don't just twist it together if you take the resistor out -- make sure you put a good splice, soldered or crimped, in the line and seal it.
Do you happen to know where the IAT sensor would be on 92 3.0?