Misfire... *fixed!*

[dahondr98]

I'd suggest that it would probably be a good move to replace all the spark plug/coil high tension leads for new ones. I've had problems before (misfiring at town speeds, but OK at highway speeds) which have been cured by a new set of leads. I've also once suffered the indignity of breaking down near the entrance to an inner city car park (different car), resulting in lots of "help" from irate motorists being held up - a faulty coil lead was the culprit there, and wiggling it finally enabled me to start it and get home. These days, I'd bin the ba****ds as soon as look at them, and replace them with a new set.

[nickk]

I was holding it at the top of the tube when i got zapped (at the 90 degree bend). When I put NGK BKR6E-11's in 1.1mm gap, it misses almost constantly. When I put a BRK6E's in, it runs better. I might try a new set of leads, just for good measure.

This morning I drove to work and it's misfiring alot less.
Only thing I have done (which was yesterday after work) is re-tap the threads for the headers because two were stripped and there was a slight no. 2 cyl. exhaust leak, sealed up the gasket with some ultra copper silicone and put the headers back on.

It seems like the more I drive it then let it cool, the better it gets. At this stage I'm assuming the T/B clean loosened a sh!t load of carbon and it's still burning it out. Maybe a bit of carbon is causing an exhaust valve to stay slightly open?

[nickk]

update, misfires gone... and i didn't do anything except for give the car a belting as soon as it stopped misfiring and then baby it when it did. Now it is fine... wtf?!

[teh_mechanic]

if you can get your hands on someone else's dizzy to try its pretty likely the problem is in there. I once had a similar misfire problem in mine and i replaced the coil and Ignition Control Module in the dizzy and it fixed it. Most of the time either of this will just straight up die and cause the car to not run, but in my case it was causing a misfire, more at higher rpm. I tried the ICM DIY test on here and it seemed fine. Changed it anyway and yeah it fixed it. I find the internal coil and ICM in b series dizzy (or d series for that matter) to be quite weak and have changed several at work. You can just try to replace one but its advisable to replace both as they work together, or just the whole dizzy if you want to the go the whole way. I'm not saying this is your problem, just that it's likely. And either that or the leads makes the most sense since it runs better on brk6e's which are 8mm gap (arn't they?) rather than the bkr6e-11 11mm gap. Smaller gap is helping the struggling ignition system

[nickk]

misfire has stopped completely now. I got a new set of leads, seems to have made a difference. I put my old set on a mates car and it makes his car detonate when he gives the throttle a stab... weird! Anyway they are in the bin now.
As for the plugs, the -11 means 1.1mm.. I've got mine gapped to around 0.8mm and it seems perfect.

[aaronng]

misfire has stopped completely now. I got a new set of leads, seems to have made a difference. I put my old set on a mates car and it makes his car detonate when he gives the throttle a stab... weird! Anyway they are in the bin now.
As for the plugs, the -11 means 1.1mm.. I've got mine gapped to around 0.8mm and it seems perfect.

If at 1.1mm you get misses and 0.8mm works fine, that means there is not enough potential voltage across the spark plug gap. Since you have changed the leads, does it still miss at 1.1mm? If it does, then I'd also look at the ignition coil, ICM and dizzy cap.