Cuts out really suddenly which made me firstly think it was ignition related. Gives heavy engine braking when it drops out, then surges a bit, then drops, and slowly gets worse until the car is stopped and idled for a bit.
I've just replaced plugs, leads, dizzy cap and rotor button and it's still doing it. Nowhere near cold enough to ice up either. Fuel pump seems to be working fine - filled a 250mL glass in about 15 secs at idle.
I had been having idling issues over the last couple of days which I 'fixed' by swapping leads 2 and 4 over to get it to backfire, and then blowing compressed air through the fuel inlet on the carby to try to clear the jet. Idling issue is now fixed but I'm not sure if my 'fixing' hasn't stuffed something else...
