[famlycar]

Hello all,
I have a code PO174 lean bank 2 reading on my van ( with 80,000 miles) which came on during some mountain driving. I replaced the air filter, did oil change and cleaned the MAF sensor. I start it up and the check engine light goes out and stays off untill I do some mountain driving again (after already driving about 200 miles on the plains with no problems) and the light comes on again. Is it the pvc valve? and how long do oxygen sensors last?
tanks!