This is a 100% bone stock 9 on 100% bone stock tune.

The issue seems to be temp related since this issue only started happening once the temp outside went below 70. During the warmer months I never had a problem with afr and even on some warmer days recently the problem went away. I always thought that the ecu would correct afr to reach target afr regardless of closed loop or open loop.

When starting the car cold, usually it will idle perfect between 14.5 - 14.9 and is pretty solid but sometimes it wants to idle around 15.4 - 15.8 and stay there. When I just tap the gas it will go back down to 14.5 - 14.9 sometimes but not always.
When cruising, it always reads afr around 15.4 - 16.2 and swings rapidly but the car drives perfect like there is no problem with the lean afr. A couple times while cruising the afr seemed to correct itself and come back down to 14.8 - 15.3 and swinging slightly less rapidly after about 15min of driving.
When full throttle, the afr is rock solid around 11.6 - 11.8 which is leaner than what the tune commands.

Besides the random inconsistent afr, the car behaves perfectly normal.. Im interested to hear your thoughts and what I should start investigating first.

 

your front narrowband 02 sensor is probably on its way out.

 

If it were the front narrowband going bad then wouldn't I get really inaccurate unstable readings in open loop full throttle? Open loop seems to be the most consistent/stable even if it is slightly leaner than what it should be. The afr is worse in closed loop situations. Although, all day Saturday the issue was present but all day Sunday the afr was perfect

 

Your thinking about it backwards.The narrowband sensor is used directly to control closed loop. Open loop reads off the fuel table. While the narrowband could have an effect on open loop via fuel trims, many tuners disable this effect. The effect on open loop would also be fairly stable because fuel trims don't often fluctuate all that much once they are settled.

 

Ahhh ok yeah you're right, I got myself mixed up with how the front o2 works in open vs closed loop. You may be right about the front o2 going bad. But why would the problem be more pronounced in colder outside temp? Maybe the failing o2 is having a hard time compensating for denser air in closed loop?

 

May be an issue with the heater circuit. The front O2 sensor is only like $50 on rock auto. I would start with replacing it. Then if you still have odd readings, replace the wideband.

You should also grab a laptop to do datalogging with and see what e fuel trims are doing.

 

never hurts to do a boost leak test too...

 

Bringing this back again since the issue is still present as it is cooling down outside again. So far all I have done is replace the wideband sensor to see if that was the culprit (yes I am lazy lol).
Cant figure out how to post interactive datazap graphs here so I posted links to them. Ignore the boost reading in vacuum, for some reason its only accurate in positive pressure situations. As you can see my fuel trims are not normal. AFR at cruise before pull is way too lean. AFR after pull seem to come back to reasonable range. Also I'm getting a bunch of knock on the 3rd gear pull for some reason. Never observed knock before on any previous pulls/logs, although it was warm outside when I did previous logging. Keep in mind this is a stock car with stock tune still. What do you think? Front o2, boost leak, post maf air leak?
3rd gear pull
Idle after pull
Cold Idle
Cruise after pull
Cruise before pull

 

If this is a stock 9 ECU and motor, you are running 6-10% lean across the rev range. This could cause the knock you mention - but I can't see any knock in the 3rd gear log. You are also 3-4 psi down on boost compared to stock. Add to that the high long term fuel trims, and it all points to a possible problem with fuel delivery.
1. Check your fuel pressure at the rail to check the health of your fuel pump and fuel pressure regulator.
2. Pull your injectors and send them out for ultrasonic cleaning to make sure they are flowing close to the stock rating of 560cc/min.
Report back on what you find.

 

You sure you're looking at the right graph? Peak psi was 19psi going down to 16-15psi, that would be stock boost settings no? Nock was occuring the entire pull anywhere from 1 to 4 counts. I imagine that if I had a fuel delivery issue then it would cause lean issues all the time and not only when its cool outside. Also if you look at the graph "cruise after pull" my afr came back to a normal range (richer) for some reason.