Possible misfire when cold.

[jmec]

Hi, I have just changed plugs and leads to cure a misfire on accel' and decel.' It worked, the HT leads were arcing through the insulation. However I now have a similar misfire like indication when the engine is cold. It happens once after half mile or so and that's it. The engine runs fine thereafter. Injectors have been overhauled a couple thousand miles ago. The boot is new and the throttle body had a new gasket fitted at the same time along with sealing the offtake. So I'm pretty sure there is no air leak. Any thoughts would be gratefully received. Cheers.

[aimlessrock]

oem or aftermarket HT leads?

[jmec]

They're not OEM. But they're not Mr Cheapys from the Yingkipongo Emporium. Brought from long standing BM specialist!

[Brianmoooore]

Presumably you notice a hesitation when hitting the throttle, and are assuming it's a missfire?
Is the TPS adjusted properly? It must switch as soon as possible after the throttle butterfly comes off of its stop.

[jmec]

Yes. With the engine off I listened for the click as soon as the throttle is opened.

[paultv]

what state is the distributor cap and rotor? New? If you had arcing on cables you may have cruddy points in the cap too, or even a crack.

Just a thought

Paul

[jmec]

Good thought Paul. I'll check that out. Thanks.

[jmec]

A clean up of the distributor cap and rotor seems to have sorted the problem Paul. Thanks.