Disappearing misfire when warm on cold days

[Puffwagon]

On 05/07/2020 at 6:01 PM, Stealth-T said:

After developing a misfire at high RPM

 

This is the most common cause of a misfire next to plugs and coils.

 

The is plenty of info about valve springs on here.

[k31th]

you test via doing a full power run then letting it idle soon afterwards and the idle will be bad compared to before the power run, if the valve springs are soft (as well as on the power run it'll sort of 'lay over' with regard to the power delivery, but that's much harder to discern the culprit compared to the idle check method).

[Stealth-T]

Thanks puff and keith. The high RPM misfire was my version of high RPM (anything above 4000) and when we pulled the plugs it was defs a couple of crappy plugs and ran fine after that. I'll give it a go tomorrow with a couple runs and see what it does on idle after, but when I do go full throttle it doesn't seem to have any delays other than the half a second of lag. Thanks for the thoughts gents!

[ilk]

[Stealth-T]

Thanks a bunch @ilk  I pulled and cleaned plugs again before re-gapping them all to exact same (realised they were a little funky when pulling them). Then used the CRC on all connectors and seems to have solved the problem! Shame I couldn't couldn't find your post when I first searched and thought I was going nuts...