Bank 1 Too Lean and Where does this plug go?
 

First of all, the engine light keeps coming on so i threw it on my OBD2 code reader and all i got was "too lean bank 1". The car has a rough idle then it idles up to about 1000 rpms at all times. Its really lacking power for a bran new car too, it only as 6000 kms on it and i swear that its 50hp short of what it was when i first had it. It has a real hard stumble between 7.5 and 8.

Second question, I have the mazda speed cold air intake on my car and theres a green plug that dangles from the wiring harness right near where the other plug connects to the intake on the driver side of the engine bay. I was wondering if its supposed to be connected?

VFAD solenoid connector......not connected to anything now...used to open the VFAD on the intake

Make sure your vac nipple is sealed ( on the manifold by the dipstick) It is likely that it is not..and that will cause the lean CEL

1. when and where was your intake put on? might have something to do with that. if it's an older one, i think maybe it's missing some screens. maybe your maf isn't secured. i dunno what bank 1 is. do you have all reflashes?

did you change or add oil? it may need oil. you should add some every few fill ups.

2. tie it back and tape it. or cut it. let me know how the second one turns out.

Like dannobre said, the nipple just behind and below the throttlebody is probably sucking in unfiltered & unmeasured air.

Cap it.

S