I have conducted the K-Test, and I have just over 5 volts going to the map sensor. What else can I try?

PV46

Since the ECM appears okay, and I presume you cleaned the main ECM ground, I would replace the main relay. Ensure you have tested all under-dash and under-hood fuses with a test light or multimeter.

I have cleaned the ground for the ECM. Car started, ran poorly for a few secods and then the check engine light came on and it is ideling fine now. Checked fuses. All fuses under hood test okay. I can't find a fuse diagram for under the dash box. The one list under your trouble shooting doesn't match the one I have. Some of the fuses under dash fail test unless I turn on that function (i.e. headlights etc.).

I have already resoldered all the solders in the main relay. I hear two clicks and the fuel pump turning on.

While I am trying to start the car and after it starts I notice black soot on the ground by the tail pipe. Could this be a bad o2 sensor?

How do I find the correct under the dash fuse diagram. The fuse box has no cover on it.

What code is being thrown? Here's how to check:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-46563-6.html#post832012

I have checked all fuses and they are okay. I haven't gotten another main relay yet. Can it be anything else. Doesn't the main relay just work or not? I am getting spark and fuel when the engine is hard to start. It coughs, backfires and barely runs until the check engine light comes on. Then it runs fine. I am afraid to take the car anywhere and especially turn it off. This is wearing down my battery and I have had to recharge it several times now. After a half dozen tries my battery doesn't turn car over anymore.

Autozone does not have a main relay in their computer so I will have to bring mine in for them to match it.