my first scooby

When i start the car up from cold it missfirers until it has warmed up but then it still somtimes misses.
changed the spark plugs at the weekend and this has made a huge difference it runs smother but still misses when cold.

I hear people talking about checking for cracks. where abouts on the coil packs do they crack? and if they are not cracked can they still be knackered? the spark plugs that came out looked like they havent been out for a very long time. so it is likely to be the old coil packs.

The car is a my95 wrx with 64000miles

cheers

mark

Jolly Green Monster

iTrader: (4)

yes it could be the coil packs.. also worth earthing the block to battery negative whcih often helps with cold running smoothness.. the original earths corrode.

The coil packs tend to crack around the end that connects to the plug.. pull off the rubber cap to check.. if the plugs had not been changed for a long time then the coil packs are probably the original and therefore long overdue a change anyway.

yes they can break down without cracking.. it is the heat cycle they go through whcih causes them to break down inside or / and crack.

Also you should use a 0.7mm plug gap if you haven't already.

Simon

my first scooby

cheers simon, all i wanted to know i will try earthing the block . and i checked the spark plug gap and they where all at 0.7.
i will have to go and skin my knuckles again and check the coil packs i didnt realise the end pulled off.

cheers

mark

Jolly Green Monster

iTrader: (4)

just replace all for at once.. even if only one is cracked.. as they will all break down around the same time.. around 90k miles or 5years roughly..

Simon

my first scooby

where is the best/cheapest place to get them from?


mark