Intermittent code P2135

Hello, I'm having an intermittent issue with my car. Hope someone that knows Hondas might be able to shed some light.

So, the problem started a few years ago, driving along and then money light came on, pulled code p2135. The engine still ran fine and there were no noticeable symptoms. Took the car to a local garage, and they pulled a few other codes on top. There was an ABS low voltage and an ECU incorrect function. We decided to send the ECU off to have it checked. I was told the ECU was fine, and that they had re-flashed it, it's been a while so I don't remember exactly what the mechanic said. Anyway, the car ran like a dream for just over a year after that.

Jump forward to 4 months ago, once again driving along money light came on but this time the engine started acting all sorts of weird. Power followed by no power, revving without the pedal been pressed and hunting. Pulled code P2135 again. I decided to take the car to Honda. They did a diagnosis and said it was the throttle body, quoted £1400 for a new one. Decided to get a second hand one instead, performed an idle relearn and all was good for a few months.

Then P2135 happened again, all the same symptoms as before. This time I bought a new pedal sensor and another secondhand throttle body. The car lasted about five miles before the same thing happened again.

Took the car to a recommended local garage, they reset the throttle position and said because I had put in a new pedal sensor the two were not matched. The car lasted about 2 weeks and yet again another P2135. The garage has checked all the wires and connectors but can't get the code to happen again to find out where the fault is. We decided to pull the ecu again and it's currently away for testing.

My concern is, that if the ECU is fine, am I just unlucky with the secondhand throttle body's or is something else at play here, like a relay or fuse?

Many thanks for taking the time to read this and hoping you can shed some light on this pain.