Originally Posted by upallnight

P0171 and P0174 are lean bank codes which always means a vacuum leak. In my case the seal between the DISA valve and the intake manifold was the culprit. If I had brought it to the stealers or an indy they would have replaced the DISA valve at a cost of $200 for parts plus labor. Going on the internet (Thanks Al Gore for inventing it) I was able to find a hack that several owners had use. They scrapped the old seal from the DISA valve and replace it with a o-ring. A 3 bucks fix versus a 200+ bucks fix.