Spark plugs

[PeteRs]

got an SRi turbo here 3 plugs are sooty/black indicating running too rich 4th plug is normal colour it does run lumpy on tickover is there a fault somewhere causing 3 cylinders to overfuel thanks

[Gsi3.2]

there could well be a fault concerning the 3 'sooty' plugs.. there are 4 injectors after all..

no management lights???

Are the plugs dry and sooty or wet and oiled?..got a pic of plug condition?..

[PeteRs]

there dry & sooty no engine light on appears to run ok apart from lumpy tickover thanks

[Gsi3.2]

it could be failing coils packs ( failing to ignite the plug every spark)... does it pull well or does it hesitate up the rev range?..

[PeteRs]

got a pic yes its got a flat spot then takes off

[Gsi3.2]

and those plugs are like that, fresh out of your new engine?...

[PeteRs]

no its my sons car hes just bought it i got an diesel cdti problay why it keeps breaking

[Gsi3.2]

Ahh.. didn't think you had a petrol.....

things that make them run rich..

1: induction kits... play havoc with the fuelling at low rpm's..
2: lambda sensors.. but i would expect all 4 to be equally sooty
3: weeping ( dribbleing injectors) allowing fuel past when they should be closed
4: breaking down leads/DIS coils..

has it had an emissions check to see what the idle mixture is like.. i.e. is it overfuelling or just not burning what it's got correctly...

[PeteRs]

he just bought it this morning but wanted me to service it & this is what i found when taking them out car is an 05 reg with 54000 think we'll get it checked out at garage as it dont seem right thanks

i have pulled the HT leads off when engine running 1 & 3 engine runs still ok 2 & 4 engine cuts out dont know if this means owt

[Gsi3.2]

what car is it?...vectra C?