What Could This Be?

[cmyr33]

hi, i've just recently picked up a series II r33. i've noticed that sometimes when i boot it, it has a really slight stumble at about 4000rpm, then at about 5500rpm. its only very slight but you can feel its not revving freely through the range. sometimes it doesn't do it though.

i was thinking spark plugs but what do you guys think

its got standard ecu, hks filter in the standard box, 3 inch cat back but running standard cat for compliance (haven't got around to changing it) oh and running standard boost.

[buggor34]

Possibly your coil packs, very common problem.

[cmyr33]

Possibly your coil packs, very common problem.

so whats the best way to check that the coil packs are ok?

[BHDave]

Sounds like a slight misfire which isn't uncommon.

Change the plugs first. A set of copper bcpr6es or bkr6es will cost about 20 bucks. Or pull out your existing plugs and check that they are gapped correctly. Factory recommended gap is 1.1mm, gap them down to .8 as you will be running a bit richer with the mods you have which will contribute to the miss.

Then start looking at the coils. There's a sticky thread at the top of this section all about them.

[cmyr33]

thanks for the help, i will throw a set of platinum's in it and gap them to .8 mm, need to do a service anyway.

[buggor34]

Good luck, it will only b something simple

[arbess]

How would one alter the gap?

[buggor34]

How would one alter the gap?

A set of feeler guages (you can pick them up from any auto store) & by lightly tapping the end of the plug on a hard surface, Ie table etc. untill they meet at 0.8mm.

Most decent auto stores would possibly gap them for you if you ask!

[No Crust Racing]

There seems to be some conjecture about whether or not to gap iridium plugs. I've got some on my desk and would really like to know =D I got the BKR6EIX-11's which as I understand have a stock 1.1mm gap, the recommended gap seems to be .8mm Should I be re-gapping these? The car is stock engine/performance wise just wanted these for longevity and this is my first service so wanted to be sure plugs were fresh.

[michael87]

ive got a non turbo rb25de can i gap my plugs down to 0.8 aswell?