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.