sharkred7

So I keep getting this code coming back after I clear it with my X4. Sometimes fairly quickly sometimes after 30+miles. At one time I believe it said bank 2 too lean.

Any suggestions?

2000 GT convertible, only mods are CAI and off road Xpipe and loudmouth II's.

I also just got a custom tune but I was getting the code before that also.

jwog666

since the code is only for 1 bank, i would say you have a vacuum leak, most likely intake gaskets

sharkred7

Do you know how to check? I was thinking maybe it was an injector problem, never thought about vacuum.

jwog666

the way i verify, is to cold soak the car (let it sit overnight), i then monitor the o2 sensor voltage with a scantool, while spraying around the suspect banks intake gasket with some carb clean. if the o2 sensor indicates a rich condition while i spray the carb clean, then its drawing it in through the gasket. since you most likely wont have a scan tool handy. i suggest taking it in to a shop and have them diagnose it, or replace the intake gaskets and see if that fixes your concern

sharkred7

Thanks for the info!

sharkred7

This may be a silly question but is there any possibility it could be the IAC? I have an inconsistent idle and the check engine light usually comes back on at low rpm? I was going to pull and clean that this weekend and or replace it.

Drastang

they say that no a 0174 can not be cause by IAC, but I had crazy idle and dying while braking deleted IAC no longer have those issues. not saying delete is the way to go for you, just that in my case yes 0174 was the IAC

jwog666

in your case, removing the iac caused all the incoming air to have to pass past the throttle plate, this may have caused a reduction in airflow that pushed your trims a tad back to the rich side, this didnt fix anything. in addition to being the most worthless mod ever, all you did was mask or cover up an actual fault. if you have a lean code, you are 1 of two things, 1 lean on fuel (not likely as both banks should flag lean codes in that case) or 2 you have a vacuum leak. i repeat do not waste your time on replacing an IAC. it will not fix a p0174 EVER

Z28KLR

Agree with the above that it is likely a vacuum leak, and being bank specific even more likely that it's the manifold gasket there. A leak at the IAC would cause both banks to run lean, as would a vac leak any any of the other plenum vacuum connections or unmetered air between the tb and airbox.

Also worth investigating is an exhaust leak near the upstream O2 sensor, especially if you hear any sort of ticking sound on that side of the car. Could be at either the manifold flange or the manifold/cylinder head gasket. And as a rare or unlikely possibility, cracked manifold.

sharkred7

The guy I bought the car from said it had an exhaust leak with the off road X pipe but not the catted X pipe. I have both. You can hear a ticking sound under the passenger side in that area. Big pain in the @55 to see if that is true and I like the off road midpipe