very intelligent thinking!!!

Air-to-fuel ratio is meaningless in a diesel because the combustion event occurs only on the vapor film on the surface of the droplets. The vapor pressure of No.2 middle distilate is so low taht away fromthe droplet surface you have no fuel or combustion.

Warm intake air will be less dense and take less power to compress, hence a gain in net power output for the fuel used...if you can get her started.

you lost me!
 

I need some convincing reading on the wai ideas. As far as i know from studying the subject, but by know means an exspert...higher ect reading to pcm=lean out condition,higher iat temp. reading to pcm=lean out condition, less maf flow to pcm=leanout condition. Then theres tweeking the voltage from the o-2 sensor on some none diesels, afr sensor on newer toys.,vibe,matrix,corolla... afr tuning is where I'm at with wifes vibe. A5kohm variable resistor in paralel w/iat will give you adjustment to get the higher air temp. reading to the pcm, but allows for tweeking if timing is retarded to much. I'm sorry guys cool air intake is better, but i do agree tricking the iat into telling the pcm that the air is warm will cause a lean out condition. Can you show me some convincing reading otherwise? If your interested in sensor tuning... https://www.fuelsaver-mpg.com/doc/TuningForMileage.html
rick
My 446ci diesel loves cool air {not cold} w/aem dryflow air filter its better than the k&n oiler i use to have, high flow dual3" exhuast.