Starting problem and CEL

[Kosimir]

Hello!

I have a 2008 Legacy 2.5 Wagon 4AT and it has been having problems with starting and recently also CEL with code P0171 (System too lean Bank 1).

The car starts fine most of the time but only if I start it by first turning the key to the ON position and then wait a couple of seconds and then turn to start. If I turn directly to start engine turns fine but it takes a really long time before it starts if it does at all. Sometimes when it's cold outside the car does this thing where it starts up but then dies and after that it's really hard to start again.

For a couple of months now the car has also been giving the P0171 code. CEL lights up pretty much every other time I drive the car. It always appears when cruising at a steady speed. Car runs maybe a little rough at idle and especially after clearing the code it doesn't seem to know how to idle and it might even stall when I start to crawl the car forwards or backwards.

I have tried to tighten all connections in the intake parts in case of vaccuum leaks. I read live data from obd and at first car runs rich but when it gets to temp all fuel trims settle at about zero. But when I give it gas long time fuel trim goes to about +20. I read online that it might be the gas pump, filter or something else in that assy so I swapped it to new. In general the car feels lighter so I'm pretty sure there was something wrong there but it doesn't solve eighter of my problems so now I don't know what should I try next. Vaccuum leaks again? Maf or Map? Injectors? Fuel pump relay?

 

[Ecmbuster]

Make sure the timing chain is in perfect condition.
Measure valve clearance.
Test compression.
Check all Battery negative connections from the battery to the body and to the engine block.
Check and or replace all the ground straps.
"Smoke test" the intake system for any possible leaks. Make sure there are no oil leaks.
Attach the same vacuum gauge to the dipstick, it should read little to nothing at idle.
Attach a vacuum gauge at the intake manifold and measure / test vacuum at a steady 17 to 21 in. Hg of vacuum at idle.
Make sure the brake booster is not leaking.
Check / test fuel pressure.
Replace the PCV.
Remove, test, clean the EGR. make sure it is not sticking.
Make sure the EVAP solenoid is not leaking.
Clean the throttle body.

If there is no access to a factory style scan tool, you can recreate the proper conditions for the ECM to relearn idle control and the correct RPM to maintain idle speed under load conditions.
Load conditions include:
Cooling fans ON or OFF
A/C request
Power Steering load request
Transmission load request
Any electrical load request
Procedure:
1. Ensure all power accessories ie: lighting, heater and electrical parasites are OFF.
2. Disconnect the battery negative for 30 minutes.
3. Reconnect the battery negative.
4. Following all steps without touching any switches or pedals. Use the ignition key only.
5. Insert key to the ON position only for 20 seconds.
6a. Turn the key so that the engine starts.
6b. Set timer for 20 minutes.
6c. Let engine idle for 20 minutes.
7. Turn key OFF and leave the key in ignition for 20 seconds.
8. Remove the key.
9. Repeat step 5 and Continue to step 10a when complete.
10a. Turn the key so the engine starts and set timer for 10 minutes.
10b. Let engine idle for 10 minutes.
11. Turn the key OFF and leave key in ignition for 20 seconds.
12. Remove the key. The ECM has relearned idle speed.

Reset the clock, radio stations and electric window one-trip features.
At times, the memory electric seats and remote fobs may not operate. Reset is required.