Automatic Idle Adjustment One Person HOW?

ESP47 said
Someone is going to have to explain to me why going through all that work to set your idle in gear and check it in neutral is better than setting it in neutral and checking it in gear.

Depending on who you are, setting it in gear requires your e brake, wheel chocks, jacking the rear up, empty parking lots etc. Setting it in neutral requires applying the e brake.

Both ways require you to go through the exact same process. One way is more work and has the potential for danger. The other way has basically no potential for danger and is the same amount of work.

The FSM also tells you to put the car in neutral to set curb idle and the RPM specs they give you are for neutral as well.

What exactly is the benefit of setting it in gear?

“What exactly is the benefit of setting it in gear?

I always set the in D idle rpm, the timing, and the A/F ratio with the tranny in D and with the brake applied. I have found that tuning an auto in D will require a richer A/F ratio, which in return gets me a smoother vacuum reading, and a cleaner take off (no hesitation or stumble) from a stop.

I also run an idle solenoid so that I can set my in D idle rpms differently than my N/P idle rpms. I like to keep my N/P idle rpms lower than my in D idle rpms which helps with keeping the engine from dieseling when it is shut down. The higher in D idle rpms makes sure that my alternator is excited at a stop (keeps the load off the battery when using brake lights, turn signals, wipers, etc.), and I like a little more rpms for a solid lifter cam at idle.

I usually have a second person sitting in the car with their foot on the brake after a major combo change to allow the tuning to go a little quicker. But after that is when I will just pull into a parking spot to reference the in D idle/vacuum/A-F ratio when I am away from the garage.
If I need to make an adjustment, then I just put it into P and make my change. Then after I make the change, I put it back into D to see the results.