Technical Missfire on one cylinder

[jb88]

Hmmm, I wonder what could have caused that?

An overly weak mixture is generally the cause of exhaust valves burning. Did the other valves look ok and was the head seat of that valve ok?

i think i know what did it.
at the time i was using tesco petrol around the time where there was all the problems with it

so now im using sainsburys petrol
jb88

 

[fingers99]

Very unlikely to be that, I'd have thought. And you'd expect a lean mixture to affect all 4 cylinders. Maybe valve clearance too tight (valve being held open too long).

 

[prompon]

Check if the air intake pipes are all connected well and good!