I bumped the remote starter terminal thread with pictures.

Make sure the car is in park

Key to position 2, on, nomcranking.

Touch a piece of wire from the B+ terminal inboard, to the connector In the white housing in the picture.

This should make the car crank and start

E Showell wrote: ↑28 Mar 2020, 16:07 (1) Could it be a bad starter relay?
(2) Is the starter on a dedicated relay,
(3) or would I be losing other stuff as well if the starter relay were bad?

Yes, Yes and No.

Bumped for evan

I'd just drive it and let it relearn. Try to "feather" the gas pedal, if you think your on a section of road where a shift flare might happen. Hopefully it will get better. I read somewhere that the relearning can take some time.

For codes ECM 3503, 3543 and 3553, recheck coil pack installation and ground wire for cylinders 4 and 5. A solid ground is essential. Make sure there is no oil or rust. Since you installed new coil packs, I've got to believe it's in the grounding or the 16 year old wiring loom at those two cylinders...

Nice hot run to get everything dry.

I have had turbo plugs require regapping after only 15k miles, so drill down on “ newish” a bit

E Showell wrote: ↑13 Jun 2020, 04:12 In the three throttle bodies I pulled at Harry's, I utterly destroyed the clips to get them off. Could not for the life of me loosen them for removal.

Spray them with WD40 and let it soak down in between the two plastic connectors. Most of the time they slide apart afterwards.

I’m not sure where VIDA is reading but you might check wiring and primary circuit cables for corrosion,

Remember the battery makes it’s presence known down at the starter so , after disconnecting the negative, remove and clean those terminals until they are shiny and bright and clean

OK. Whenever the idle speed is not controllable the ECM does random cylinder canceling to keep speed lower (prevents startling driver and runaway car allegations when throttle is punched instead of brake...). Lumpy idle and sometimes misfire codes from this FMEM. The air leak code is the ECM saying ...

E Showell wrote: ↑19 Jun 2020, 15:55

Idle overspeed control?

A form of limp mode.
If signal from sensor on the foot pedal doesn't match the throttle body its a safety issue.