Pls Help! Lack of power mid rpms - possible misfire
 

Hi guys!
So I have my gt86 2013 for 3 years now, only came to realize that it has a serious lack of power when I drove a couple of other 86 a few months ago;
I was thinking the clutch needed replacement but from 3 years ago up until now the car drives exactly the same... From approximately 2k till 4k rpms, flooring the gas pedal, the car accelerates hardly and it sounds like a truck if you know what I mean. Then past 4k rpms the engine sounds smooth and normal and the acceleration is amazing. Even when revving in neutral I could see there's a problem when I compared my car to the others of the same year btw.

I told my mechanic about the acceleration problem 2 years ago so we had the spark plugs replaced but that didn't change anything.

It only had aftermarket suspensions and Invidia N1 when I bought it, I then installed a catless header 10 month ago and 2 weeks ago got hold of an OFT so I put the stage 2+ tune.

When I put the catless header I didn't get any DTC for 10 months... but as soon as I got the stage 2+ tune I got an O2 sensor dtc which didn't come back for 2 weeks now after I cleared it, and also a P0301 (Cilynder 1 misfire) and this one comes back systematically (engine light blinks every couple of minutes when it occurs around 2.5K RPMs).

What's more interesting is that I have another ECM from a 2013 FRS and whenever I put that one instead of mine I Do get P0301! but also P0453 P0463 P2401 P2419 C1201. At this point I'm wondering if my ECM has been tempered with in order not detect these codes :bonk:

The lackn of power mid range is called the Torque Dip. All 86s had it. It's not broken, that's just how the engine behaves. If you have catless headers you need a tune specifically for that. Which stage 2 should be, but some people do have catted headers. The codes come and go because they aren't properly turned off for whatever reason. Your tune shoyld turn off the cat related codes because you don't have one anymore. The misfire is likely because you have the wrong tune loaded and the computer is trying to "fix" it, but can't.

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Ashikabi it's not a torque dip, there's a big performance difference between my car and the other 3 frs/86 that I drove that were also from 2013.

Sorry but I forgot to mention that I get some shaking at around 2500 rpms and that's when generally the computer detects the misfire, sometimes it's extremely rough.

Try resetting the ECU by disconnecting the battery or even retuning it. My FRS (catted, OFT) & BRZ (catless, ECUTEK) would have that problem whenever I'd disconnect the battery or update the tune. Sometimes, I'd have to reset it 2x. I'm not sure about your errors though.

Changed the ecu back and forth multiple times, tuned and untuned also multiple times...
The difference in power before and after the header and tune is minimal. last 86 completely stock I drove was way faster than mine with that header and tune.

Ok. That wasn't clear in the first post. Still sounds like tuning to me. What all mods do you have?

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Invidia N1, EL headers, body kit and suspensions that's all :iono:

You said you loaded stage 2 tune. I know "stage 2" is super vague and there is no 100% definition of it. Was there a description on the tune stating that it was intended for catless headers and catback and nothing else? Really only the headers matter. But if the tune included modification for an intake, like MAF scaling, then that would indeed cause problems

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Yes it's a stage 2 plus tune, OFT mention on their website that it is intended for catless headers, stock airbox which I have also

But are you supposed to have any other mods? I find it hard to believe that headers alone qualify as stage 2

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They state on their website that stage 2 is for catted and 2 plus is for catless, also anything after the headers is compatible

What about intake? Can you link that page?

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K that's pretty clear. You are running 91+fuel right?

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