2004 ford expedition with a lean code in bank 1. Have replaced all of the ignition coils, fuel filter, uppper and lower intake gaskets, had the fuel injectors cleaned and checked, and still i have a rough idle and a lack of power. Looking for a true solution the mechanics have all given up and I am running out of money and patience. Thanks, Randy

A lean code for an entire bank would seem to point to a bad O2 sensor located in the bank exhaust head pipe somewhat ahead of the catalytic converter. Take the vehicle to Autozone or a similar business to get a free computer scan--it may reveal other fault codes. Do any of the cylinders have a regular miss? If two adjacent cylinders have a miss, there might be a blown head gasket between them--a compression check would reveal that. It might be time to find some mechanics that know what they are doing! Good luck!

O2 sensor..have a code check done at auto parts store for free..that should tell the problem for sure..but my advice is 0xygen sensor bank 1...

Could be the upstream oxygen sensor is faulty and is causing a lean code, have someone with a scan tool watch all the oxygen sensors. compare the 2 front ones and make sure they are fluctuating properly