Right, i've got a 2.3 strokered evo 6, running a gt35, custom manifold, hks 272s, power FC ECU.

I'm having some problems with what i believe to be the sparkplugs.

I'm now gapped at 0.5mm which seems to be about the best, i've tried about 4 different types of plug some fail and won't boost more than 1.2 bar, NGK BR8EIX seem to be the worse.

Do i need to go for a COP setup?

I got it running better this morning, but only for a short while and then it starts to miss again, I was using an NGK PFR6 plug i think it needs to be cooler but its about the only plug that is ok with the boost level.

On the wideband i was reading 11.5s at 1.8bar as i upped the fueling to around 11.1-11.2 the missfire became worse.

I'm going to try some cheap BR8ES tomorrow to see if that works.

My HKS plugs worked ok 45 heat range, but after a couple of WOT run's they seemed to missfire really badly untill it cooled off.

Any idea's?

 

Try looking down into the two coil set ups and pull the spring that seats on the tip of the plug out...sometimes that spring looses resiliancy and needs to be stretched out to sit on the plug snug....no pun intended lol.

 

I don't think its a problem with the leads to be honest.

What do you mean by two coil setups?

An upgraded original setup?

Wouldn't I be better to COP straight away save all this hassle?

 

Sorted with BPR8ES gapped to 0.5mm.

 

Running stock plug wires?