I have a consistent misfire at around the 3500 RPM mark on my Sapphire Cosworth track car. A cough and a splutter, nothing more. It hesitates then keeps going.

I'm not too worried about it but I think the car is slightly overfuelling too. I was going to investigate the CPU to see what chip is in there but I thnk it's standard. The engine is standard 2WD with turbo restrictor. I have just changed the leads, dizzy cap, rotor arm and spark plugs.

Any suggestions as to what to check next? I thought I'd check all the connectors carefully but if you have suggestions as to what the likely contendors will be I'll start there.

Thanks all.

Charlie

PS. First track day booked at Brands Hatch on 3 July. So far I have: fitted new driver and passenger seat, new harnesses, changed oil, filter, changed brake fluid, fitted new plugs, leads, rotor, dizzy cap, fitted 16 X7s with wets.