TPhong

About a week ago, I took my MY00 out for an afternoon drive and notice it running very strange. As I accelerated, the car seemed to intermittenly bog down and sounded like a WRX. Every time the car began to bog down, the CEL would flash. After running the OBD, it came back with a P0302 (2nd Cylinder Misfiring) code. I checked, pulled, and replaced the spark plugs with NGK Laser Iridium plugs. I cleared the old codes and fired her up, and she purred like a kitten. A few days later, I noticed a slight bog here and there. I've noticed that at an idle, every once in a while, there is a slight exhaust pop. Also, around 2,000 rpms there is a slight stutter, but it is very apparent at 6,000 rpms (when VTEC kicks in) there is a stutter (sounds like too much/not enough fuel or air). The stranger thing is it will stutter at 6,000 rpms if I am WOT, but if I just gradually let it climb, no stutter whatsoever. Steps I have already taken to try to figure out the issue.
1.) Changed plugs and added a little bit of Oil
2.) MAP Whack
3.) Cleaned IAC Valve
4.) Swapped MAP Sensor with another AP1 (thanks Gyoza)
5.) Added Concentrated Fuel Injector cleaner
6.) Sprayed Carb cleaner on most of the hose connections (thought it could have been a possible air/vacuum leak)
7.) Changed Oil
After each step, it seemed to have remedied the issue, but it would come right back. It hasn't thrown a CEL since the plugs were changed. Comptech Intake and Exhaust are on the car and have been for about 40K miles, and she has just broken 125K miles. Any suggestions??

thecbrman

injectors? a friend of mine had the same problem until he replaced the injectors and it went away. he did try the fuel injector cleaner and the car would run fine for a few days then it'd run like crap again.

TPhong

I added the injector cleaner a few days ago, but I haven't noticed any difference.

GyozA

Hey don't the MY00 and MY01 running too rich? You think if we swapped out ecus if it'd help?

GyozA

Hey dude, here's some stuff that might help if you have a cylinder 2 misfire if you didn't see them already.

https://www.s2ki.com/forums/index.php?showt...0&#entry4471437

https://www.s2ki.com/forums/index.php?showt...&#entry12742120

Maksim

At WOT it is running open loop and not using oxygen sensors to control fuel. What it does use are MAP, Coolant temp, and TPS. When it is running at less then WOT it will use oxygen sensors to smooth the AF so you might not see the issue there.

So I'd re-check those three things...

If you have an access to obdII scanner see what the long term fuel trim values are...

TPhong

Maksim, I'll check those three things as soon as I get off work. Hey Blake, if you're bringing the ECU, we might as well swap out the coil packs too!

TPhong

I don't know if this helps at all, but I noticed today, while at a red light I had the A/C on and the popping was a prevalent and more frequent.

GyozA

Yeah, That sounds good. You've just been driving it like normal too right? Did you pull the injectors? If not we can do it later. Also, I'm going to bring the video camera's whenever we do. Someone has to know what it is on Youtube or on this site.

drewmob

I'm pretty sure there was a thread similar to this one earlier in the week. A guy said he was bogging under WOT and it eventually ended in a dropped valve and dead motor.

You've been on the board long enough so I'm sure you know more about this than me, but have you pulled the cover and checked the valves? Be very, very careful or this could get much more expensive.