Thanks mate. I'll have a bit of a read through some of the other forums.
I thought it might be the coil packs but I wasn't sure if they would cause the Engine dash light to stay on.
Today when I kicked over my 1999 ER34 GTV Skyline, the engine light stayed on and the engine (and the rest of the car) was vibrating quite a bit. Does anyone have any idea of what the prob might be?