1JZ miss fire when cold ...

[Cressid@]

Hi all,

I have some weird miss firing with my 1jz. Hope someone can point me in some directions so I can try to fix it.
it only happen when it is cold in the morning and the first 5 mins of driving.
when ever I put my foot down, I can feel its stutterring.
And only sometime that it is stationary, the engine rev drops low and high, it is also happen for few seconds, it's gone once it is warmed up!
I suspect the plugs, I got iridium plugs about 40000kms by now.

Any ideas? thanks,

[pato]

plugs,

also mine seems to want to hit boost cut as well early in the morns,

i did have the same problem, replaced the plugs and it fixed it, allthough it does come back everynow and then tho to be honest.

[IN 05 NT]

plugs,

also mine seems to want to hit boost cut as well early in the morns,

i did have the same problem, replaced the plugs and it fixed it, allthough it does come back everynow and then tho to be honest.

cool/denser air will cause boost spike, if you have it set close to the boost cut, it will spike and activate it,

coil pack plugs been replaced?....very common and 90% cause of any misfire for a 1j.

iridium plugs have a 100k life span, they should be fine, unless its been running rich or lean

[JZA70 R]

does it have programmable management?

[Cressid@]

I will give the plugs and coilpacks a check! might replace them with normal copper plugs see if that is the problem. Many have praised about copper plugs.

coilpacks and ecu are stock.

[Cressid@]

one more question!
if my engine is stock, does re gap the plugs do anything?
will it helps stronger sparks?

[jet81j]

i had misfiring problems with my 1j and i tryed re gaping the plugs and it worked for a bit it turned out to be the coilpacks the whole time. i THINK the gap you should have is 0.8mm.

[JP]

1J cressida I've got here would hardly run the other morning when it was really cold, ended up being the HKS plugs as the culprit. Replaced them with some Denso PK20R11's and it ran perfectly.