Possible R&r? Only 10Psi, Happens Randomly?

[niZmO_Man]

Probably a coil pack plug issue, but at least it's fixed now.

[Ben C34]

must have been loose/dirty connections. There is no way iridium plugs would have worked any better than Copper plugs, especially with a bigger gap

[hop1308]

i thought it was the coil packs, tested them all individually by turning the car on and checking for a spark. all of them had spark.

i was shocked too at seeing that iridiums with 1.0mm gap would work better than coppers at 0.8mm gap. but who knows, guess thats just one of the many mysteries of the skyline lol.

[GTSBoy]

It wasn't the spark plugs.

[hop1308]

with your experience Ill have to believe that I guess. ive kept the copper ones I bought, might swap them in one day and give them another go if the iridiums give me issyes

[scotty nm35]

The Iridiums shouldn't give you issues, they are designed to last 100,000k's. They cop a fair bit of flack from the 'copper plugs are better' brigade but I have had no issues at all with my NGK Iridiums. The Denso ones are not as good from my experience.

[mad082]

The iridiums in my 33 only lasted about twice as long as the copper ones I put in (sold the car with the copper ones, so don't know how much longer they went, but the copper ones in my Commodore daily have done 60,000kms).

And if you changed the plugs back to iridiums and the misfire went away after the copper ones made it worse, then you must've not plugged a coil in properly or something like that. Regardless of the different materials, a smaller gap gives a stronger spark, so is less prone to misfiring. A bigger gap gives a longer spark, which is what you want, but is more prone to issues