Misfire when stationary

[Dr Mike Oxgreen]

Engine developed an intermittent misfire on my way home last night. Running perfectly, except every time I came to a halt the engine would start missing after 5-10 seconds of idling, then misfire badly as I pull away. But when I get up to about 20 mph it suddenly snaps out of it and pulls normally again.

I'm thinking this is heat related. It was hot yesterday, and I'm guessing that the under-bonnet temperature was tipping over the edge until I got moving again.

The coil was replaced a few years ago (failed in France in the heat) and is a Bosch unit, so it shouldn't be that. Could it be the amplifier module? I also have a new set of HT leads waiting to go on, but I doubt they'll fix it...?

And it has an MOT appointment today - d'oh! It'll flunk the emissions if the misfire happens. I'll have to ask them to keep the bonnet open to let the heat out, and pray it runs okay.

[Dr Mike Oxgreen]

Well, it passed - so the misfire couldn't have happened during the test.

I've now fitted the new HT leads (bog standard Lucas ones to replace the blue Magnecors) and taken a test drive - no misfire. So who knows?

[semaj]

I had that on the wife's 430, so same as you, dumped the Magnecors and fitted Lucas Land Rover leads and no more problems! £15 off Ebay, bargain!

[Sardonicus]

Nothing wrong with stock leads nice easy fix

[ch427]

Do stock leads allow you to remove the extenders or are they a little too short?

[jojackson4]

Depends how you run them but you need some heat proofing
Socks or extenders

[Dr Mike Oxgreen]

I left the extenders on. They're looking a bit tired but still sound. I found it much easier to wiggle the extender off and then fit the HT lead to the extender before refitting the extender. The new leads are a more generous length than the old ones, especially the king lead which is at least 8 inches longer than it needs to be. So I need to do a bit of tidying up to take up some of the slack.

I've also ordered a new ignition amp; a nice fresh one will do no harm, and I'll keep the old one as a spare.