I just had a similar problem (until yesterday) and after trying plugs, plug gaps, coils, plug leads, timing map, and boost leaks the problem still persisted. In my case it was always around 6300 6500 rpm and was a soft stutter and then kept going.

So to narrow down the causes I switched off NLTS and launch control and in neutral I just stepped on the throttle lightly and went through the whole rpm range up to 7500, and everytime I would get the soft stutter around the mentioned rpm range, so now at least I knew it wasn´t load or boost or timing related! Since I had a newer cam angle sensor laying around I changed that and the problem was totaly cured!!.

 

I had a problem where mine would only break up under boost. First I tried a new sparktech cop bacause I thought it was the coild packs. Then I replaced the cam sensor and still no luck. Next came the MAF sensor and I still had the problem. Finally I replaced the MAP sensor on the manifold and the car was back in business.

 

Well replaced my plugs again and wires and car was fine for three pulls regapped plugs to. 028 and it felt like it gained 50hp and was fine for two pulls then broke up again.. changed plugs again no issues galled at. 22 after three pulls breaks up...

 

Hi Guys,
today ive went for a re-tune and at first everything looks fine as i am happily getting 330whp with only 1.2bar (Low) of boost and this is the wonder from GSC S2 cams but when my tuner set for 1.5bar of boost my car miss fire...My mech advise me to go for an Injectors cleanning and do anyone knows what is the healthy omps reading for a plug cables?
Curently im using ngk spark cables.
My spark plugs when took out from the engine all look whitish on the plug tip.
Hope can settle the problem after cleaning the injectors tmr.

 

My injectors are brand new ID1000CC's Got my wastegate working on my car and it doesnt break up at 15psi its perfect... ANything higher then 20psi brakes up... Fuel CUt is bypassed has new plugs now... new wires... new battery... new coilpacks... Still breaks up. I am completely out of ideas. If I put in new plugs in Its Fine for 3 pulls after that the plugs seem like they die and it breaks up again. Im lost...

 

Wonder will putting an extra resistor help?

 

well when you installed the spark plug wires, did you put any dye eletric grease in the coil boots?? are the coil boots cracked?? are they on right??, if you dont hear pop into place then there not on right. On a personal note i ended up havin a small misfire issue, which come to find out was due to the fact that my spark plug socket the rubber insert where the back of the plug goes in ended up gettin lodged in my #2 cylinder after reinstalling plugs and i didnt realize it...so stupid on my part. but my tuner caught it for me, so somethin stupid and simple is usually the big issues haha

 

What is your AFR during all of this?

 

Afr during initial spool up is 12.0 in low load once boost kicks in 4000rpm-7500rpm Ive got her running kinda rich 10.3-10.5

 

Everythings brand new and yet they click into place. And no I didnt use any electric crease in the coil boots. And I'm pretty confident there on right lol. 15psi seems to be fine now just cant really go any higher then 20 with out her breaking up. Im about to just go back to stock heat range (br7es) and see what happens. Ill just run a tight gap.................. Merry Xmas everyone!

 

Holy frisbee man lean it out and it should go like a raped ape.



aaron

 

lol yeah I usually run 11.5 through the power band but with this missing issue Ive been weary. Ill get it figured out.

 

Flooded under boost, especially with low timing, will pop bang spit and sputter. Leaning it to 11.5 will be fine, if its still doing it then there are other issues. I havent been able to get a car to run misfire free at 10.5 over 25psi, so assuming low timing and maybe a WB thats a little off and it can easily be the cause.

 

damn dude that is the best piece of advice Ive had so far. Ill try that out tomorrow. Its been snowing here in VA so Havent really had a chance. I honestly didnt want to touch timing to much until I get on the dyno but Ill increase it gradually and make a set of det cans from Lowes lol.

 

I think that JohnBradley is saying to bring the AFR to 11.5 and see if that helps, not to increase timing while you still have AFR of 10.xx

Hope this works out for you.