dgm458

2008 xD, owned by my girlfriend. No mods. I'm a pretty good shadetree mechanic, but this has me baffled.

Driving full steam down the interstate one day, it dies. Tow it home, it's showing a code for low oil (engine shutdown). We change the oil/filter, runs fine. Days later, it shuts down again. No code is showing, it just won't start. We test fuel pressure and it indicates that the fuel pump is out.
We buy a new fuel pump and install. It will run, but it's rough. Really rough. Getting a code indicating something with the oil - old oil or wrong viscosity. I changed the oil (not remember what weight was used the last time) to 5W-20 with a higher performance oil filter. The oil code cleared.

During this time I also replaced the alternator as it was beginning to whine.

Took the vehicle to a garage to have diagnostics run. They said to replace the coils and plugs. It was not showing a code, but the diagnostics in the ECM indicated such. I did that. Still wouldn't start.
Took it to a different garage, they replaced the plugs (again), cleaned the intake system and got it to start by spraying into the throttle body to get some ignition.


Now, it's throwing Code P0171, Lean in Bank 1. My code reader actually gives me this code twice - one confirmed, one pending. I cleared the codes, it does it again 10 minutes later. The oil light is now lit up again also.

The car is difficult to start. It's taking multiple cranks and it almost whispers at first like it's trying to start, but not quite there yet. Once it's idling it runs really rough at idle. To get it to go, you have to get the RPM's up over 2000,
gently let out on the clutch and let it idle up to speed. It will not go up hills because that requires giving it gas and then it bogs down. Giving it too much gas at idle causes it to die.

Again - new alternator, fuel pump, plugs, coils and a clean intake.

The air filter is good. I find no visible vacuum issues. The battery cables are good. In my opinion, the fuel injectors are a little loosely fitted into their slots.
The turn with ease. The last mechanic that looked at it said it was not the O2 sensor.

Looking for some inputs guys. It's a great car, but she's about to run it over a cliff...

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CXTKRS1

Check the resistance of the oil pressure/level switch maybe. How is the IAC? No new codes?