So today I was driving and after I stopped at a light when I took off until 2k rpm was fine then all after 2k it was stuttering and it feels like a misfire (never had one before so I don't know exactly) It was boosting fine and all but it was just sputtering and misfiring under boost and under any accerlation really. I could hold speed but if I tried to accelerate much at all it would start again. It's fine at idle but it does seem to make this little blip and soft pop while idling. So what I did was I just ordered some spark plugs for it. I ordered 4 NGK BKR9EIX and then I ordered 4 NGK R5671A-9 copper plugs because I heard those are better for running on e85.

Car info: AP1 2000, GT3076R turbo. 512WHP. ID2000cc injectors. AEM v2.
Does new plugs seem like the direction to go? Any advice? Thanks, nick

Also no CEL is on. Maybe because AEM v2? No OBDII on th V2 either

 

Could it be the known issue we see from time to time when the ECU is adjusting to changes in environment? I only experienced this once but as I did more research on the forums it seemed like its a well known occurrence on stock and boosted s2ks alike. Mine did it once and went away. I also have a friend who experienced it on a ultra low mileage but well maintained stock s2000 and his experience was the same.

 

I don't know man. It's never done it before and it was doing it for like 35 minutes. for around 15 minutes then I stopeed turned it off reset the ecu by unhooking the neg terminal and started it and let it idle for a while then drove the 30 minutes back with it doing the same thing

 

There's a misfire guide on here. Are you getting a cel?

 

It's your plug and play injector cables. Feels like the car as 0 power. At idle isn't not as pronounced, but if you pull a cable injector at a time, if you don't notice a change in idle, that's the culprit

Mine suck ass too

 

What makes you so sure it's this and how do I replace them?

 

It's an easy test. When it happens, disconnect one injector at a time. If idle doesn't change then it's the problem cable or injector (most likely cable)

 

So while the car is idling pull them on at a time and if the idle changes then they're good?

 

Correct. You should be able to hear the car idleing a little rough which means it's firing on 3 cylinders, if you pull an injector that's good and go down to 2 and you will know it's not that injector and try the next. One of them will not make a difference, that's the bad one.

I'm just dealing with this now myself, it happens sporadically. But when it happens it continues to happen with very brief moments when it doesn't miss fire. I had to bend each pin slightly and compress the female pin side to fit more snug. Today I haven't had any issues.

If you hook up the laptop and have the O2 feedback compensation set up, you should see the ECU dumping fuel to compensate for the missing injector too.

PnP injector cables are known for this. I'm not saying it's 100% that, but it's a good place to start and very easy to diagnose.

 

You could be losing a coil pack. One of mine went bad and was almost exactly how you described. Noticed it after taking off from a light one day. Worse under acceleration, came and went a bit. I was able to see the CEL for it though since I had Haltech at the time. Showed a misfire on a certain cylinder. I swapped coil packs around and the misfire followed the busted coil pack.