I have been having trouble with my wife's 09 Accord. For the past year it's been having issues where it will lose power. The rpm gauge will drop to zero, mph, all dash lights will light up, radio goes out, but the engine continues to run. It's been doing this for at least a year now. Took it to the local mechanic and he changed most of the relays as well as replaced the ignition switch. He checked the battery cables to make sure they were tight. The battery is fairly new and the car runs perfect even though it has 168.000 miles on it. Last week the engine actually died in a mall parking lot which freaked me out a bit. This is the first time it's done this, although when I hit the ignition to start it again it started immediately and it hasn't acted up since--almost like I "rebooted" something. Just before the engine stalled it went through a series of what I described earlier with the dash lights, radio went out, etc. Also, I have never seen it throw up a code or a check engine light. Not once.
Any ideas of what the problem is? The only thing I can think of is the ECM board which has not been changed. But, as I said the car runs perfect--it doesn't hesitate, doesn't misfire, starts immediately, and runs smoothly. I refuse to give up on it. It has been a great car for us for 11 years and even though my wife bought a Subaru Forester and I drive a 2022 GMC Canyon I refuse to sell it because I love the 5-speed stick plus it's a Honda. Any help is appreciated.

 

Intermittent problems are tough to diagnose unless you can test when the car is acting up. Please avoid throwing parts at the car without some testing. This can complicate diagnosing the root cause.

Do you have a scanner that can read all engine codes? It is with a shot of you have some codes to give you a direction to test.

Is there anything consistent when the car acts up? Like only while the car warms up, or hot/cold weather, or rainy days, after filling up with gas, etc.?

Was any other work done on the car right before this issue started happening?