First time poster...long time reader. I know this is a Ford forum, and I own an F-15 4x4 but, I am helping a buddy on an s-10 2.2L 4 cylinder. After a clutch and rebuilt head it runs well except at an idle. Have searched high and low for any vaccuum leak or disconnected wires with no sucess. I shot codes po172 and p1441. Any idea what to check? The manual with my code reader is too vague. Please help!!