Been to croft today and the car is suffering from a very bad misfire.

The car was set-up 200 miles ago which included a new chip, new cps, new rotor, new plugs, new fuel reg.

The problem is from around 1500rpm and ranges intermittently through to 3300rpm. As you can imagine it's very difficult to drive.

I've replaced the plugs with a new set of 071's and exactly the same.

The car when first started runs very lumpy when driven slow

Any ideas???