I have an 05 with 122k miles. All original, no mods except K&N filter. Check engine light came on a couple weeks back. And it started to simply run a bit rough at idle for the previous few weeks. Since I had never replaced plugs, I went ahead and did this. I reset the CPU and it seemed to run a bit better for a day or so, but then it started to run rough again and finally the check engine light came and has stayed on. Took it to Autozone/discount and had them check the codes. I got two codes: Misfire on all cylinders and then I got secondary O2 sensor code.

The cars runs decent. Pulls fine, but perhaps a little sluggish, vtec still engages. I've read the posts in the under the hood forum about misfires and things to check. Tried the map whack, etc. But still no idea. Havent checked the ignitors or fuel injectors but it doesn't run so rough that I think that is the problem.

If anyone local is knowledgeable and can help me run through all the possibilities then that woul be great.

Lmk, thanks, Clay.

 

Reminds me of back a couple years when I had my mustang, seems to me like it might have something to do with your coilpack, especially after you getting a misfire on all cylinders.

 

replace the secondary 02 sensor or if it doesn't look to bad, soak it in some white vinegar to clean it off. That usually causes a rough idle. Personally I would just buy a new one.

 

Thanks. Guess I'll try O2 sensor. Didn't think they went out often. $200 gone

 

often??? you stated 122k miles on the car, right?