P0506 (IAC) and a collapsed vacuum elbow

[sam&steph]

My '03 x sport (4.o sohc) started having rough starts after new battery was installed. Also noticed low rpm's and shuddering at idle. CEL P0506. Several threads here pointed to the IAC which I cleaned- With the plastic cover off, I noticed the 90 degree vacuum hose was collapsed as if the intake was suffocating. I know there are lots of threads about this but none addressed both issues. Would a bad PCV cause an airflow restriction? Im going to clean the MAF sensor next but the I feel something ielse is wrong. No apparent leaks or noises.

[thepotroast]

Originally Posted by sam&steph

My '03 x sport (4.o sohc) started having rough starts after new battery was installed. Also noticed low rpm's and shuddering at idle. CEL P0506. Several threads here pointed to the IAC which I cleaned- With the plastic cover off, I noticed the 90 degree vacuum hose was collapsed as if the intake was suffocating. I know there are lots of threads about this but none addressed both issues. Would a bad PCV cause an airflow restriction? Im going to clean the MAF sensor next but the I feel something ielse is wrong. No apparent leaks or noises.

Your PCV is located on the other side of the motor from your IAC. It's on the back of the intake manifold between the motor and the firewall on the drivers side. A bad PCV has little to do with idle issues. You could always replace the IAC, they are about $40 new online. Even with a freshly cleaned IAC, the actuator inside could still be failing...and with a collapsed hose as well, that sounds like your issue. I would just throw a new IAC on there, especially if your're throwing a code for it.

[sam&steph]

thanks for the advice potroast- I just replaced the soft hose with radiator hose (#80400, trimmed down a bit) and ordered the IAC.

[foxfire556]

dont mean to sound dumb but what is IAC?

[BigRondo]

Originally Posted by foxfire556

dont mean to sound dumb but what is IAC?

Idle Air Control Valve.