Not the right spark plug and they stick into the cylinder head too far. I hope you didn't put the IK22's on a 2JZ.

 

Iridium plugs are better then platinum when it comes to any type of FI. With Nitrous, however, you have no choice in the the matter. Platinum plugs will not hold up and will eventually melt!

Go with NGK iridium in any FI VQ motor, its a better choice.

Also ALWAYS GAP YOUR SPARK PLUGS!!!!!!! I cannot stress that enough. It only takes a couple minutes, but its critical to have the correct gap. They do NOT come pregapped. There are tons of other applications that these plugs work for, so you cannot assume the gaps are for our cars. Hope this helps

 

Denso Iridium IK22 (2 step colder) COME PREGAPPED period - 0.4 and only $9 on ebay. Excellent plugs. HKS are great but ridiculously expensive. My buddy with 400whp G35 had random misfires w/ NGK Iridium IX "6" , replaced with IK22 - problem gone.

 

ngk>denso anytime of day. Period.

 

Did your friend re-gap the NGK's? I just ordered a set.

 

Evil, what gap do you have on your NGKs?

 

.044, I didnt go smaller cause spark wasnt blowing out. The larger the gap, the better the spark...but for FI many of us are blow out the spark and a smaller gap is needed. Hence the need for aftermarket ignition box's to increast the power in order to increase the gap without blowing out the spark. So far so good for me with the .044. I might have to go smaller for the 150 shot tho.

 

Those "random misfires" are due to incorrect gap. All he needed to do was close the gap up slightly. Hence why I said you ALWAYS need to gap your plugs. If the denso's come pregapped to .4, then thats slightly smaller than what the oem requirement for our cars are (.44) hence why he didnt get any ignition problems simply cause the gap is smaller, which is what he could have done with the ngk's. Blaming a complany for a user issue is silly, especially if it wasnt even you who had the problem personally. I've run 2 dollar ngk's in my 11 sec talon for years now and its always outperformed other "high priced" plugs.

When I got my iridiums in, most were pretty close, but pretty close doesnt cut in my book. You need to be exact and to make sure ALL the cylinders are running as close to each other as possible. So i adjusted the plugs accordingly and so far its been problem free with multiple runs and as my daily driver.

my 2 cents