Reply to thread

Message: <blockquote data-quote="hottwheels04" data-source="post: 1443065" data-attributes="member: 8550">This is an update to it seems a never ending problem. few months back I had code 176/172 to do with176=hego (ho2s)  sensor fault /always lean172= hego (ho2s)  sensor fault lean,I figured bad 02 sensor or 02 sensors. I posted this and many agreed.I replaced the 02 sensors check engine light went off.Now fast forward it is back again so i rescanned it. now its just code #172. I found bad vacum hose replaced it. checked for exaust leaks and new 02 sensors and still have a lean code #172.code 176 is gone but 172 still172= hego (ho2s)  sensor fault lean,I can drive around town 1st through 3rd gear the light never comes on. but soon as i get the highway and in 4th and 5th gear 50-80mph the light comes on blinks goes off for 1 good minute and will blink on and off several times then come on and stay on after being on the highway.what else could it be? could the 02 sensors even it  being  a new 1, is bad?  i know that code is to do with passenger 02 sensor. I was thinking of buying a new one again maybe got a bad 1? cant figure out!! I  even had a  ford dealer and buddy who owns a shop working on mustang go through the whole car they  cant figure it out. only thing I can think of since i put new heads on it compression is diffrent so tune is old tune. is it maybe running to lean up high since on an old tune so it burned up the new sensors?   was told it could be  A bad fuel pump /  maf going bad?  since all vaccum leaks fixed checked and new hoses. no exaust leaks and car runs fine otherwise.</blockquote>