My GFs car is a 1999 Ford Explorer with the 4.0 SOHC six in it. She had a check engine light come on a few weeks ago, and before consulting me took it into the mechanic. The mechanic told her it was just a failing o2 sensor, replaced it, and told her not to worry about it unless the light comes back on. The light came back on very soon and she brought it over for me to look at. I pulled codes P0174 and P0171 from it -- too lean on both banks 1 and
- After doing some research on the web, I haven't come up with much except for a possible TSB for a leaking intake manifold gasket or leaking intake manifold o-rings. I was wondering if someone could tell me how difficult/expensive these are going to be to replace and either what I can do to make sure it is really the problem, or what I can do to make sure that I'm not chasing/replacing a million different things before it is repaired.
Thanks
Rob