So I just installed a new catted mid pipe and upgraded ignition coils from bhr. I had had a code for the downstream O2 sensor which was replaced with the new cat. O2 sensor code went away no check engine light after the install, but then after the second or third time I drove it now I have a p0661 code. I can't help but wonder if I f***** something up or didn't do something that I needed to. I feel like these things are related but I have no idea and I have searched and I can't find anything similar to my problem. Any words of wisdom would be supremely appreciated.

Also I apologize if I posted this in the wrong 😇🖖🏿

 

It's possible while you were working on the coils you did something, but it could also be a coincidence.
It happens.

This thread has good info if you disregard the noob flaming.

https://www.rx8club.com/series-i-tro...ay-1-a-236699/

 

Ok. Not really what I was hoping to hear but thanks for the reply!!

 

P0661 is usually caused by the SSV vacuum solenoid (the middle one, marked with a white dot) behind the upper intake manifold, towards the firewall. I just replaced this due to the exact same code and it has fixed the problem since. This happened about four weeks ago. Before the replacement, the CEL would come on almost every time I drove the car when the engine got up to operating temperature.
Access is a little difficult, but there are pretty good threads here on the forum and some useful YouTube videos (besides several not so good ones), showing the process. Essentially, you'll have to take off the UIM to replace it.
Probably a coincidence that the code popped up now, after the other work got done.

 

Could have just agitated a vac line and caused a leak.

 

that’s particularly the part that deserves attention; this must be POSTING AND YOU week (it’s a video on youtube, check it out at around the 1:10 mark)
.

 

 

So I pulled pulled out the intake box and coils checked my vacuum lines and plug wires. Put everything back together and no more check engine light.

Bullet dodged? We shall see.

Thanks for the input people!! This forum is a life saver