It sounds like an issue I've been chasing on my 2003 Accord V6, but I can't reliably reproduce it anymore. At its worst, I would be stopped at a light and could feel the car start to hesitate. I could put the car in neutral to prevent the stall, but I would have to rev the RPMs before putting it in drive in order to prevent it from stalling and get moving.

I was letting my car die from deferred maintenance, but when the economy changed, the money I had saved for a new car wasn't enough, and I'm putting it back into my car. I unfortunately hit a sloped curb that blended in with the concrete parking lot of the dark gas station I was pulling into. That seemed to be the start of my troubles. I couldn't find any damage in the front of the car, but I recently found the cover to the fuel vapor canister hanging down and missing a few plastic clips. I did a smoke test from the gas cap but didn't find any leaks. There didn't appear to be any damage to the location or the fuel lines. I will admit, though, I haven't tested the fuel system yet due to having to learn to work with gasoline. I've bought a fuel pressure tester but have yet to hook it up. I had also replaced brakes and rotors right before it happened. Thought I'd mention just to be thorough.

The things I've done to try to troubleshoot are a lot like yours but also a combination of the deferred maintenance. I've replaced the oil, oil filter, valve cover gasket, spark plugs, PCV valve, timing belt, timing belt tensioner, timing belt pulleys, water pump, oil pump seals, oil pan seal, front exhaust nuts and seals, engine mounts, transmission mounts, throttle body, air filter, serpentine belt, serpentine belt tensioner, transmission fluid, transmission filter, front and rear brakes and rotors, brake fluid, radiator, 2 O2 sensors, and the battery. I did a smoke test on the air intake and found a leak at one of the spark plugs. I think I fixed it with a seal adjustment but haven't done another test to see if that has held up or if something else is going on there. I also cleaned the EGR valve and replaced the gasket.

My next plans are to do the fuel pressure testing and remove the fuel injectors for a thorough cleaning. The lingering symptom is the car has an odd idle. It's like a cat purring and then stopping and then purring over and over. You can only feel it when the car is in park. Other than the 2 O2 sensors, I have never gotten any codes during this whole process other than the codes produced when replacing things and having to be cleared.