Fiesta spark plugs - dws
Ford Fiesta 1.400 cc petrol Duratech engine 2003.

I have just changed the spark plugs on the above car at 31,000 miles. I have set the gap at 1.3mm, but there is now a slight missfire at slow speeds.
Is this the correct measurment for the gap, as the car was running OK before I changed them.
FIESTA spark plugs - Collos25
Spark plugs are set at the optimum gap when you buy them you should not have to change it.
FIESTA spark plugs - Carrow
According to NGK they should already be pre-gapped at 1.0 mm. Part number TR5A-10. What came out & what did you put in?
FIESTA spark plugs - Mike-H
Apart from checking the gap is correct, you may have inadvertently cracked the ceramic whilst fitting one, which could cause the problem. It's quite common, as it's quite easy to do if the socket is not held plumb square . 1.3mm doesn't sound too much for a modern system. What happened to an N5 with 25 thou? Mike
FIESTA spark plugs - Screwloose
What happened to an N5 with 25 thou?

After being superceded by the N9Y, they became obsolete when the 2.6ltr 6-pot Land-Rover was dropped in '79? [The last vehicle that I can recall with an N5-only spec. USKD.]
FIESTA spark plugs - Mike-H
What a memory screwloose! My very first summer job prior to going to college to do motor engineering, was in a Land Rover dealership, changing gearboxes under warranty, as they were all faulty (1970) I reckon I could still do one blindfold now! On the odd occasion I was entrusted on collecting parts, I seem to recall the part number for a set of contacts that went with the N5's on a 2 and a quarter petrol was Lucas 473153. Might be wrong; the memory plays tricks! My Triumph bike engine takes N4's when you can find 'em. Mike
FIESTA spark plugs - bell boy
i reckon dws didnt put ngk or bosch plugs in personally, or as said broke one in the fitting stage,i did the same last week. :-(D
dws.............Iif you have broken one be sure to stick your oover pipe round the fred fred before removing spark plug as the porcelin is tougher than steel and will wreck your engine if any falls into the congestion chamber.....
FIESTA spark plugs - puggered
could be coil pack and/or leads possibly
FIESTA spark plugs - percy
The early Mondeos were 1.3mm gap, later ones went back to 1.0mm. I put mine down to 1.0mm, no apparent problems. If you make the gaps too big you will encourage misfiring and endanger the coil pack. (On some motors you might also damage the ECU). So put them down to 1.0mm.
FIESTA spark plugs - Red Baron
1.3mm for a modern-ish engine is enormous. Try 1.0mm maximum. 0.9mm should do as well.
If you've bought the correct spark plug, then the gap will be correct.

Ask Honest John

Value my car