99 Accored, 2.3 F23A1, no CEL, limp mode.

1999 HONDA ACCORD, V4 - VTEC, F23A1 ISSUE: no CEL, stuck in limp mode, very rough idling.

Currently experiencing a mind boggling issue that I have not ran into and am having trouble getting clear results from advice found elsewhere online.

So, here is the story:

Today my plan was to replace the Oil Seals on the Valve cover - the ones that keep oil from splashing into the spark-plug tube. Two were torn, and my 1st cyl was filled with oil. Ran fine prior to changing this stuff out.

Took off valve cover, popped out oil seals, inserted new ones, replaced valve cover. New plugs, same wires. Car starts, runs smooth, took it for a ride to the auto store for miscellaneous stuff. Smell coolant burning, see smoke from hood, pull over into a parking lot and checked the situation.

Below the throttle body, there is a small water inlet tube gimmick that is screwed on by three philip head screws. What remained of the little tube (you would place a hose over with a clamp), it was severely corroded. Broke about 1/3rd of the way down the male piece. This transfers coolant.

Took it home (less than 2mi) and it overheated really bad. 300 feet from the drive way and it goes into what I would think is limp mode. Can't rev past 2500rpm, bogs down real bad. Figured it was going into a self-protect mode because of the temp sensor reading (uncomfortably high). "No big deal, will reset the computer by disconnecting the ground and that'll fix that."

300ft later, pulled into the driveway, turned car off after parking. Took off Throttle Body to inspect the inlet to see if enough was there to put a new hose on (the old one was complete junk). Success! Just the perfect amount for a snug fit and no leaking.

Reconnected everything as they were before. Disconnected battery ground for 20 minutes, started up car. Stumbling, not running well and will not allow to accelerate (in park) past 2000. Was able to reverse the car out (idling) and then go into drive and get to the end of my road. Drove it down the block, can't get past 2500 or so in Drive I believe. Will have the computer force the car to "bog down" below that RPM level. While in Park, if I were to "floor" the pedal, the engine bogs down and dies completely. The car HATES neutral - the idle goes erratic and will bog the car down to a complete off.

Noticed after all this, the car's odometer (as the car starts) looks weird... the numbers don't display correctly, however after warming up for a few minutes, I came back and they looked normal. "Weird, but OK." (right?)

The dash is not throwing a CEL code, but it has a MAIN'T REQ'D light, which I have not tried to reset yet (through the dashboard process) after the previous oil change.

I have verified the CEL light does in fact turn on when the car's first turned on, but goes off. Car idles around 700/750, a little rough feeling, and as mentioned before, if I gas it to try to get past that level, the car will die stutter and die out.

From looking online I had the impression that if there is a bad ECU, the car could "go into a cruddy running limp mode" but would throw out a CEL code for you to verify. Yet... no code...

Been poking around all day on the net with this. I've "reset the idle" as well, to no avail. Has anyone had this issue before? I am wracking my brain on this and as you can imagine, a home with two working and one car makes for a troublesome commute.

Thanks for any help you could provide.

EDIT: minor corrections/edits to the story for clarity. Side-bar compliance.

TL;DR: Car overheated, went into limp mode, can't get it out of it. No Check Engine Light.