My 4.6 1999 is misfiring, but only a little bit . checked with the nano with which it give options as to engine tune, I have a vague feeling the engine tune was for 4.0 . I'm going to reset to original factory settings with the nano for a 4.6 . The rubber pipe petrol filler was old, replaced at the garage they said they had to "tilt the reservoir/tank" to fit it, I hope no pipes/tubes got squashed inadvertently thus restricting petrol flow, causing occasional misfires. A MAF change is also on the cards. Which plugs and leads do people on this forum recommend for my 1999 4.6 HSE just done 32000 kms about 19840miles, plugs leads coils ? Also where is the ECU for the engine located Please?