Originally Posted by DaveW
Richard, the misfire you are having has similarities to what I suffered with my GDI, and sadly I never got to the bottom of it. It came on first on an uphill stretch, and all power vanished, but it would start and idle perfectly. It never went into limp mode. After some throttle pumping it would rev to the limiter in bursts, and then stutter back to a steady tickover. It did this about six times on that journey, in which I filled the tank. It felt like water in the fuel (and may have been) or an electrical glitch. By the time we got home, it was running normally. There were no error codes. I changed the relays, and checked the fuses, and because the tailpipe was blacker, decided to replace the cat, and sensors as emissions were rubbish anyway. So it remains an enigma.

That's as close to my issue as I've heard from anyone else on TM Dave. When it first happened three or four years ago there was no fault code despite uncomfortably driving car to the next stop 15 miles away as I was leading a group. The only consistency is that after a wait of around three minutes the problem clears and on one occasion didn't reoccur for three years! Another thought given this issue is that the adaptive mapping somehow gets corrupted and the three minutes wait with engine off allows it to clear or reset. Backing this thought is the fact once manifested the problem never clears whilst engine remains running.

Richard

2018 Roadster 3.7
1966 Land Rover S2a 88
2024 Royal Enfield Guerrilla 450
1945 Guzzi Airone