Misfire w/ Usual Fixes done
 

Alright so I Have an 04 6spd with 117k miles.I'm having a misfire when I put aa good amount of throttle down in 3rd gear or higher. It will slowly go up, but be very jerky and laggy. Then it'll flash the check engine light. The sound goes to like a dying chainsaw rasp. But the speed inches up. It does the same in 5th or 6th, but barely climbs up in speed. It's idle isn't too rough, but I can hear the misfire at idle from the exhaust my car doesn't stall at idle at all.. Also generally if I'm going over 90 and give it any gas its bound to happen. It doesn't flash in 1st or 2nd, even if I floor it, it just goes to about 7k and jerks a bit and lags. Like it loses a bit of power. I just need some insight.

So far Ive:
Seafoamed the car
Cleaned the MAF sensor
New coils & wires (Aftermarket DRL racing wires)
New plugs installed 1500-2000 miles ago.
Cleaned the ESS & did the 20 break stomp
Checked to see if my midpipe (I have a black halo racing midpipe) was clogged by driving hard and looking , it wasn't glowing (but I did find a leak around the transmission area)
Got my fuel pressure checked & it was good
Replaced my downstream O2 sensor, however I noticed when I took it out, the old one wasn't one I've seen that goes in an rx8. So maybe it could be the upstream one is the same way and causing it bc its not one I've seen you can get for an rx8?

The only things I haven't done are taken off my midpipe to fully look inside, replace my CAI pod filter (which i didnt think is that bad but you never know),new fuel injectors, or get a compression test.

One thing I did notice was when I seafoamed the car it seemed to get a little better in the couple of 1-2nd gear pulls I had, no more lag up top. But the misfire at idle was still happening so


Does anyone have any idea? I really could use some help. Thank you.

Misfire w/ Usual Fixes done
 

Does the midpipe have a cat?
Check to make sure all plugs/ coils and wires are connected properly, in the correct order and are snug.

What brand of new coils did you use and have you actually tested the coils or the wires? Just because they are not that old doesn't mean they are not malfunctioning. I just had a primary O2 fail that was bought brand new only a few thousands miles ago.

Seafoaming could have fouled the plugs if done wrong but if it was doing the same thing before you seafoamed then that is not likely.

No, I have the Agency Power midpipe which doesn't have a catalytic converter. And I've made sure all wires and coils and plugs are secure. When it threw the P0300 & P0302 codes, I switched the plugs coils and wires to the other rotor and apparently now it just throws a P0300 code but doing the same thing as before.

They were some ebay coils because i couldnt afford thd BHR ignition kit. But they "seem" pretty decently built. Keyword, seem, i know. And the problem was occuring way before the seafoam, but the seafoam did seem to help the 1st and 2nd gear at high rpms. Is it possible theres just a lot of buildup somewhere in the engine or midpipe and a couple more rounds of seafoam will help?

Seafoam is a waste of time and accomplishes nothing.

As for the rest, well you can keep guessing and assuming or you can start testing and getting clear answers. But there are plenty of warnings about the Ebay coils so before you make your next purchase I suggest searching here first and problems like this can be avoided. Also if you can't afford OEM ignition coils then I highly suggest that you sell this car ASAP.