HI

Just purchased punto HGT 2000 a couple of weeks ago, has started misfiring and jumping badly, checked spark plugs, 3 are new, 1 old (despite the fact that the dealer was meant to service it!) and the chamber has a lot of white powder in it as has the one next to it but not as much. Any suggestions what the problem could be despite the knackered spark plug? What's causing the white powder?

Thanks in advance!

doesnt the white powder mean the mixture of fuel/air is too lean??

White deposits on the plugs are signs of overheating which may be caused by a lean mix, wrong type of plug or poor cooling.

If you have white deposits in the pots then you may have a blown gasket, especially if only in one or two pots.

could it be caused by damp? there is a slight rusting on the lead to the worst plug?

rust on the lead???
one the HGT the leads to the plugs are just wire's with a plastic cover on them as it uses a electronic firing system not HGT leads so these dont rust
could you put any pictures up for us
did you check the cars service history have the services been done on time ???
are all fluid levels at right levels. when you open the oil cap whats it look like on cap and in engine

How many miles are on the clock?

Maybe try changing the HT Leads. :S

the HGT dont have ht leads

The part of the pug which is rusting is the very small rim of metal at about half way down the length of the plug, I assume where the spring is attached.

Have checked oil, cap and engine clean. Services have been done at regular intervals. Have it booked into garage on Friday. Deffinitely needs a new set of plugs, garage not done their service correctly! All levels correct?