Running rich, throwing code: p0172
 

Ok, so I finally got a little more information then what I previously stated. Here is a recap of all information I have gathered:

Modifications:
NST Crank Pulley
Megan Header
Descendant Cold Air Intake
Tsudo Catback exhaust

Above mods removed both cats, in case that information is necessary. The car will throw on two lights: Check Engine Light, Slip Indicator. The car will kind of bog out, usually only in idle. Idling at 500 RPMs and boost to 700 RPMS on its own, without A/C on.

The code it is throwing is: p0172, which appears to be something to do with a Vacuum Leak, Dirty intake, or something wrong with the fuel.. something, if I'm not mistaken.

Checked the piping, and everything is secure.. so I doubt it's a vacuum leak.. and seeing how my 2011 Scion tC only has 19,000 miles.. I doubt something wrong with the fuel pump or something of that nature.

I've had the intake for a little over a year and, as stupid as this sounds, have never cleaned the intake. Could this be my problem? The car never gave me a problem in the past, up until now.. Should cleaning the intake be something I start with and see what happens?

Thanks for all the information and help :)

Did it start throwing the CEL after installing the header?

Do you have something that tricks the O2 sensor cause your #1 Cat is out. Perhaps that device is defective. Also maybe a bad O2 all together could cause this. But I dont think the dealer will like the fact that the Megan Header has removed the Cat...they will blame that.
I sure hope its not the NST Pulley causing these problems. Have you tinkered with any other hoses lately. I once connected a hose wrong on the fuel evaporator thing.
Wish I could be more help.

At first the CEL showed up after the header, until I got a CEL eliminator for the header.. then it went away. The CEL only comes on in combination with the Slip Indicator.

Do you know what that is? I dont know what your talking about.

I popped the same code this past weekend. I have an AEM CAI and an axleback. Cleared the code and all is well, I think is it because of the CAI.