4.0 litre misfire

[Timothy Ashtray]

Hi everyone. My lovely Jag developed a misfire today on the way to work. It seems to happen when I'm going uphill (so under load) but not necessarily when I simply accelerate. Any ideas where to start looking?

cheers

Tim

[JOE-DOT-COM]

Hi Tim

Could be one of many thing really, Have you checked for any fault codes?

If I were mine, I'd start with a new set of spark plugs, but also it could be a coil pack

if you change the plugs, they should be a nice light brown/tan color, if you get one plug that's black/sooty that could be the problem one

if plugs don't cure it and you are getting a odd colored plug compared to the others, swap the coil pack with another cylinder and take it for a run and see if the dirty plug shifts to the new position

also check the coil pack connectors for corrosion, this can also cause this

cheers

Joe

[Timothy Ashtray]

Cheers Joe, I'll have a look at the plugs. Failing that, I'll get it plugged in. 

Thanks a lot

tim

[Timothy Ashtray]

Just out of interest, could the misfire be related to the sudden cold snap?

[JOE-DOT-COM]

Hi

Could be, bit a damp in the right place, can give you a right nightmare

cheers

Joe