I just changed the spark plugs on the Zetec-S. The ford service guide lines for spark plugs are 40,000 miles between replacement.

The plugs i took out were well worn on the tips of them. The new plug were all gapped to 1.3mm (as per guide lines) and i measured the gaps on the ones that came out, they were rangeing between 1.6 - 1.7mm. Does that gap sound rather large to anyone considering the correct gaps are 1.3 mm ?

i guess as the gaps are wider the spark must be later, does the ECU of the Zetec-S detect this and make adjustments to the ignition timing to compensate for the wider plug gaps ?

p.s i wont be leaveing this set of plugs 40,000 miles again, they will be changed ever 10,000 service without fail no matter what Ford say