uk impreza turbo misfire
 

hi guys,
i just drove back from work, exiting a corner there was a slight hesitation in acceleration in 3rd at about 3000rpm as i planted my foot.
this has developed by the next junction into a misfire, in the cruise it is fine but on wot 2.5 to 3000 rpm and up there is an occasional misfire, and pop from the exhaust. it only feels like one cylinder, whether it is always the same one who knows.
there is no check engine light and did a fault test and nothing came up.
i'll take it out for a spin later see if it is getting worse.
its a standard car, boost solenoid cleaned, maf, lambda, leads and plugs replaced about 10,000 miles ago.
anyone got any ideas
thanks, andy

ok an update, the misfire happens if you plant the throttle at low rpm, as the boost is rapidly building.
most noticable in 2nd gear. once it is on boost it runs great, also runs ok if you stay off full throttle and let the boost increase more gradually,
any ideas?
thanks, andy

What leads did you use?

magnecor

I'd blame them causing it, replace them with oem leads

update, the engine is fine when cold and it would appear after gentle driving
it is only when you start having fun it starts missing, new plugs and a fresh tank of vpower tomorrow
see if that helps

could well be a HT lead breaking down. i had magnecore on one of my old cars, i dont rate them tbh.

check the leads and make sure none have rubbed on something and worn through etc, and even that they are still clipped on properly.

also worth a look is the actual plug ends, as they can unscrew sometimes. (the bit the lead clips onto)