Engine misfire :-(

[Deleted User]

Misses badly but then once engine is warm its fine....

Seems to be one cylinder thats misfiring with no spark at the lead. (When it had warmed up I removed the lead from plug and saw good spark).

Once engine has warmed up its fine...

Already changed spark plugs (why not its cheap). What next? Plug leads? Distributor cap?

jaydeeuk1

Yeah, I'd try that. Or swap a lead from a working cylinder first (both ends obviously )

scheming_gypsy

My Celica had a corroded lead and would misfire when driving, so it might not be leads.

Although, my Jeep has exactly the same problem. Are you losing coolant as well? mine is but there's no puddles to say it's leaking, no mayo or heating issues to say it's the head gasket.. So i had a quick Google and found:

Not sure about the jeeps but a lot of the chevy engines (Vortech) had intake manifold gasket sealing problems allowing coolant to seep into the cylinder and mix with fuel and be burned, so no puddles, just a loss of coolant and sometimes if the condition was allowed to worsen a engine misfire due to fouled spark plugs. A competent repair facility should be able to pressure test your coolant system and identify the leaking area.

So i'm guessing, if it's possible, that moisture is getting into the cylinder and causing a problem. When the engine warms up the moisture evaporates and the problem clears..??

[Deleted User]

Pretty sure its spark not getting to plug when its cold.

Took one lead off when engine was running and got no spark. By the time I got to work and it was running OK, I took same lead off again, saw spark when lead got close.

thefishdude

if you have a dizzy cap check that for cracks or check the contacts inside see if one side is badly corroded. if all ok and spark not getting to only one plug then must be the ht lead.