Misfire

[Jezza-7]

Today, i thought i would take it for a little ride to make sure everything was running ok. After about 15 mins i put my foot down, hit boost but when i hit around 4-5 k revs i had a misfire problem. I backed off and headed back. I tried one more time and it was fine. A bit weird i thought. Any suggestions? Oh when i started off the car was covered in ice and was very cold, wondered if that had anything to do with it?

[xandyx]

the same is happening to me, but at lower revs. i haven't ride the car that much, but i'm thinking that might be fuel pump.

when it does that, it gets better if you press the clutch and gas 2 or 3 times? when i do that, it gets better for a few miles and then happens again.

[Jezza-7]

I only recently, 5-6 months replaced both pumps though.

[breadman]

Jez, I'd of thought it was more of an ignition issue being that it did it under load? What's the condition of the leads, plugs, rotor arm and cap like?

[Jezza-7]

Leads, cap, plugs, rotor arm all replaced december 2009. Had a the dizzy replaced in may/june last year (not a new item but was pretty much new)

Got a head going on soon and its gonna have everything new on it. Might even get a new ignition coil.

I personally think its the leads. Might take my leads off my mk4 polo and swap them over and see what they run like, unless theres a difference between them?

[PeteG40]

how old is your coil?

they are generally shit!

[Jezza-7]

Never replaced as fas as im aware. Today i drove it again to see if it would happen and it didn't, it was fine. Strange. Maybe the car didn't like how cold it was.

[breadman]

Being very cold shouldn't make any difference really Jezza. I'd say the extreme cold just high lighted the problem of a tired electrical component.
I'd start with a new coil first as everything else is fairly new.