p0302 misfire
 

Hello guys.

Going home from work today I got a flashing cel, code p0302. This is the second time I had a misfire, last time was about a year ago, I'm not sure though if it's the same code. Last time I took it to the dealer right when it happened as I was nearby. They told me one of my coils had gone bad and that they needed the originals as I have the BHR ignition installed. I didn't have them available at the time, but they came to the conclusion that it was just a bad connection in one of the ignition cables since everything was fine when they put everything together after doing some testing and everything's been working fine ever since until today. One or two times since then I have gotten a p0420 code when cruising at highway speeds for longer periods of time (>30 mins). I visually inspected my cat which was fine and i've passed all the inspections where they measure exhaust levels since then, and the code went away after just a couple of days by itself so I came to the conclusion that it was just occasional and nothing to worry about. I have the BHR catted midpipe as well i might add.

So here I am today with a new misfire. A few minutes before the cel showed up the car was "jerking" during some accelerations and sometimes I had to give some extra gas going uphill, but it returned to normal when the road leveled out. So where do I start? Coils? Plugs? Wires? Cat? I'm eventually going to take it to the dealer but I want to have some idea about the cause beforehand since I don't really trust those guys. Please tell me I haven't fucked something up myself. :crying: The car only has about 47.000km on it (about 29 000 miles?).


Thank you, you guys are the best!

Read this sticky
https://www.rx8club.com/series-i-tec...t-here-222280/

ditto what RX8Soldier posted, check out the misfire thread

Your p0302 is a rear rotor misfire. And your p0420 is catalyst system efficiency below threshold.

Ok thanks. I somehow missed that thread in my searching.

Hello everyone, im new here and im sorry if i post this in the wrong spot ( i have done some research but i cant find the answer im looking for - and i cant start a new threat) but im having a P0301 code which is misfire on cyl. 1 (i know its a rotary thou)...I've checked the link provided by gwilliams6 and i have literally tested almost everything? before i begin... i have a 05 shinka 6 speed with 125k miles and i believe those are the original miles? im the third owner and i bought it to work on it (it was on a small accident)... i just did a tune up (last time the last owner change the plugs and everything was at 100k) and a decarb process, however, every time i start my car on cold weather it shakes and feels rough and the check engine lights blinks and stays on (sometimes it goes off)... anyways, I have changed the coils 3 times, the spark plugs twice..i have cleaned the MAF and the ESS along with the NVRAM process...I checked my cat (which was gutted by the previous owner) and the light still comes on? i honestly dont know what to do and i need help... some notes on the side... before the decarb process, it didn't start rough at all (just took forever to start due to tune up service due)...when its warm and i start the car it starts normal (i think i have good compression on the engine since it starts right away and i haven't notice loss of power?) however, i have notice that my coolant disappears which makes me believe i have a failing cooling seal? (yet i don't notice several smoke coming out of my pipes - just the regular smoke when its cold)... my OEM coils which i ordered through amazon have a different part number from the box... the box says "B" and the coils say "C", does that mean i got the fake ones?...so i guess the big question is... do i have to replace my engine?

also i havent checked the fuel pump because honestly, i have done most of the misfire trouble shooting and nothing has worked so far, so if i need a new engine, i would like to know before hand.. that way i stop spending so much money into this, trying to figure out whats wrong and actually get to the problem..
Again sorry if this is in the wrong spot and my grammar.
thank you for reading btw.

The only way to know if you need a new engine is to do a compression test with a rotary specific tester.
However you could still do troubleshooting to determine the cause.

How many times have you replaced spark plugs and coils? Sounds like you'd save money and lots of time if you brought it to a rotary mechanic and have them diagnose the problem.

That's what mechanics do.