Bought an xr3i, it has a misfire at 3000 rpm. You can rev through it but it needs sorting. Any suggestions to the cause of it??? Previous owner put in a kent cam, ported and polished it. Some one told me it could be the cam so changed it to standard but it still has the misfire??? Any suggestions???

 

have you checked the basics?spark plugs/leads,cap etc?

 

if its none of the above get a tester and go round the elecs make sure everyting is powering right

 

i had a problem like that on my mk 4. turned out to be a bad connection on the alternator. hope this helps!