Re: Puzzling problem (JTD)
ok, maybe not. Once it got wobbly you would probably have problems all the time.
If it idles smoothly but misfires on acceleration, my best guess would be a fuelling problem. Enough for idle, not enough for throttle. Perhaps it is the fuel rail pressure sensor then, where a tuning box could be plugged in - it tells the ecu what the pressure is in the rail, tuning boxes fool the ecu into thinking its lower than it is, so it turns up the pressure.
Your sensor could be reporting higher pressure than is there, hence low fuel pressure when you need it. Low rail pressure will cause fuel starvation intermittently and poor or no spray pattern from the injectors.