LET running problems

[Wazza024]

Right i have running problems with my let, when started it won't idle properly and is missing when revving slightly. Its almost like it's not firing right at all. Its got a coil pack on it, and i looked at the coil pack and it's a bosch 1. Now i took the plugs out and number 3 plugs has some marks on it where it looks like its hit maybe the piston but the plug is still in tact, i changed all 4 plugs and its still doing it. It's running piper cams and i checked the timing and that looks correct the marks seem to line up where they are meant to be and also turned it over by hand and feels fine. The car was running fine up until this happened. I looked at the injectors and the colour of them is yellow. It does have a lamda sensor on it to. Any help would be greatful as not dealt with these engines at all.

[Rich]

For a start a let wont be running a coil pack unless its not on standard managment? Will be dizzy, orange cap?

[Wazza024]

Sorry it's running emerald management system. It used to be dizzy by the looks of it but blanked off to run coil pack.

[Nova_Tek]

checked for any fault codes?

[Sloth]

if tis on emerald you need them to look at it, but if the plug has marks id say theres something inside thats not right....

[Wazza024]

I was going to phone emerald tommorow and see what they say. Fault code wise i don't know if ill get anything out of it if it's running on the system but maybe im wrong. They done all the mapping on it aswell