I don't know if anyone can help but the last two mornings I have started my car up let it warm up on the drive as I normally do before I go anywhere and it ticks over fine and it drives fine off boost but as soon as u get in to boost for the first 7 miles of driving it misfires and holds back but after the 7mile it is fine all day until the next morning where it all starts again.
It is my00 turbo 2000 wagon
it has got chav valve turbo back exhaust I think they are 8mm ht leads.
New spark plugs gapped to 0.7 new fuel filter and oil and filter change as of yesterday

thanks in advance for all your help

 

Has it done this since the new plugs, or before the plugs were changed. I had a Mazda 3 MPS which was heavily modified and I had trouble getting the right heat range of plugs. If I went too warm I'd have no issues with the misfiring in the morning, but the car would misfire under heavy load like wide open throttle pulls on the motorway. If I lowered the heat range of the plugs, the car would no longer hiccup on the motorway pulls but would splutter and misfire in the cold mornings. A temporary fix was to pour in a bottle of octane booster into the tank (a recommendation by a local tuner) and this solved it but got pricey. I finally sorted it by switching from denso plugs to NGK to get a better match of heat range

 

was getting a misfire on my 2000 turbo when having it mapped, replaced the coil pack and the miss fire was gone off boost but still there when boosting, i replaced the plugs and thought all was well but after a few miles it came back . so it got a new set of leads and i couldn't believe the difference much crisper pickup and misfire was totally gone ,

 

I have had the car for just over a year and it has had the same plugs every service it just started to do it yesterday morning so I went home and changed the plugs but that has made no difference there is no fault codes loged in the ecu.
I am wondering if it could be a faulty coolant temp sensor.
thanks for your replies

 

try new leads, didn't look like anything wrong with my old leads but obviously a bit tired i got my new ones from euro car parts for £44 and made such a difference.

 

I will try my old ones on it.
at the mo its got magnecor ones on it and they aren't that old.

 

I would change the plugs again / fairly common bad plug or gap - you should always gap your plugs yourself even if they are pre- gapped
& having a bad plug in the pack isn't a rare thing at all

 

Agreed. Check the gaps, then go for a completely different brand. If that works then all is good!

 

At 7 miles its only just up to full operating temp. Probably is a plug issue. But i personally wouldnt be to bothered providing its ok once fully warmed. It will keep you off boost till its up to temp. Just coz the coolant guage is up to temp, doesnt mean the rest of the motor is

 

Thats what i was thinking,but couldnt be arsed typing it