I have 2009 fx4 with 128000 miles. First start of the day or after sitting awhile is very rough. It starts and you touch the gas and stalls. Mileage horrible at 10.4. Changed cop and plugs and rough starts continue and mileage dropped to 9.6. Then I get engine light. P0150 and p0130. I then took it to the garage and had the computer update. Rough starts still continue and no improvement on mileage. As a side note if it helps. Not even a year ago i was getting mid 14ish for mpg. What should I be looking at now? Thanks or any advice!

 

From those codes and those symptoms; I would get your exhaust back pressure checked. You might have a clogged cat.

Or it could be an electrical issue with the wiring; grounding, infestation, or broken wires.

 

https://www.obd-codes.com/p0130

https://www.obd-codes.com/p0150

Potential Symptoms

Depending if the problem is intermittent or not, there may be no symptoms other than MIL (malfunction indicator lamp) illumination. If the problem is constant, then symptoms may include one or more of the following:
MIL illumination
Engine runs rough, missing or stumbling
Blows black smoke from tail pipe
Engine dies
Poor fuel economy

Causes

Usually the cause of P0130/P0150 is a bad oxygen sensor, however this isn't always the case. If your o2 sensors haven't been replaced and they are old, it's a good bet that the sensor is the problem. But, It could be caused by any of the following:
Water or corrosion in the connector
Loose terminals in the connector
Wiring burnt on exhaust components
Open or short in the wiring due to rubbing on engine components
Holes in exhaust allowing unmetered oxygen into exhaust system
Unmetered vacuum leak at the engine
Bad o2 sensor
Bad PCM

The articles cover troubleshooting.

 

Thanks you for the info.