hi everyone i have got this in for the day trying to find out why it's misfiring and backfiring. i have scanned it and no codes the engine idles smoothly and picks up revs well in the workshop if i do it slowly, but if i snap it it misfires and backfires so far i have smoked it, scoped the coils, the crank sensor, oxygen sensor, replace the spark plugs it's still the same i have checked the emmisions and they look good i wanted to check the timing but there is no easy way to do this without destroying the cups there does't seem to be a cam sensor to compare it with the crank sensor. any ideas?