I was pulling off the highway onto an exit ramp, I released the gas to coast down and it was almost like the engine shut off but I'm not sure if it actually did. The speedometer dropped to zero, the check engine light (which has been on due to the P0420 code which I will soon be addressing) went off, but the car was still rolling in D4. Tried giving it gas but no response. Turned off the ignition, pulled to the side, and restarted the engine and all was fine. Super weird occurrence. Any idea what would have caused that to happen?

 

Speedometer & lamps shutting down suggests a flaky ignition switch? That mimics the behavior of switching off the key. Most other reasons for the engine stalling would result in warning lamps & the speedometer would still read as you coasted to a stop.

 

Seems logical to me. Of all the research I did on my symptoms, the only logical explanation that I found was a flaking/failing ignition switch. I'll troubleshoot it and see what I come up with.

 

There was a recall on ignition switches for some Accords of your era. It couldn't hurt to call a dealership to find out if your car was part of that recall.

 

I checked online and put in my VIN but there were no recalls.

 

My daughters car is a 98 Honda Accord LX. When we got it and took it in for a new timing belt, they said there was a recall on the ignition switch and they will fix it for free.

You could call a Honda place, just to be sure about those ignition switch. Those online things are not 100%.

 

I emailed them with the VIN and there was no active recall for it.

 

Regardless, it's worthwhile to check it.

If you can make it stall by wiggling the key, then it is a flaky switch.
Unfortunately, if you can't make it stall that way, it doesn't really prove the switch is OK.

Recalls that might have already been done; those might replace the switch with a new one, but not redesigned and again prone to future failure.

 

Tested the switch and it was fine. Even jiggled the key while in the RUN position and continuity was good in every position. What else could be related/linked?

 

Here's an info page from YourMechanic on that error code (might be useful - gives full diagnostic details of the code).

https://www.yourmechanic.com/article...-jamahl-walker

Misfire, fuel injector, oxygen sensor...some of the things on the list look like they might have actually contributed to your problem.

Hope this turns out to be something simple for you.