Engine on bro saph cossie missfires on high boost, after 4000 revs. Changed leads, plugs and hoses. Also have sprayed sensors with wd40 and the problem is still there. Anybody have an idea?
have also tried turning boost down but still no joy

 

GAP ON THE PLUG WHAT 1s DO YOU USE?
CHECK ALL THE TIMING AND BITS YOU CAN

 

Usually an engine missfiring is associated with timing, so i would check that out and make sure it is running correctly.

 

i had this problem mind you was on a zetec not a yb , it was the throttle position sensor had gone and the air flow meter , and a split in the air flow pipe so was sucking in more air after the sensor , best to get it on a diagnostics thats wot i did , i wa spulling my hair out not knowing wot was wrong because it had been serviced by myself just be4 it played up

 

maybe buy a group a coil.

 

Check your coil connections for rust
I also had this problem and the coil connections where rusted and i cleaned them and problem was gone

 

It was the spark plugs. thanks

 

Jon,

Just out of interest, what was wrong the plugs?

Wrong grade, Gaps, Worn....???

 

ONE OF THEM WAS DIFFERENT FROM THE REST AND THE GAPS WERE DIFFERENT.

 

does it splutter pop and bang or just miss?

 

Splutter Pop and Bang....