I bought a 2013 evo x off second hand not too long ago. As I learnt more about the car, I started monitoring fuel trims recently. I have an AEM afr gauge in my car, one thing weird about my car is from what I see from the afr gauge, things look fine. During cruise afr swings between 14-15 generally, sometimes it goes down to 13.5 to 15 (which is a bit rich). Idling afr swings from 14.2 to 14.9 most of the time. WOT afr is around 11-11.3. But from what I see from fuel trims, LTFT cruise is always over 5%, recently moves from 8% to 9% even hit 10% at one point. LTFT idle goes over 5% sometimes as well. From the afr gauge, the car doesn't seem like it's running lean, number is under 14.7 most of the time. The car pulls strong and doesn't really go into any limp mode. I tried to check the fuel pressure regulator hose and it's secrued and tight.Air filter is reletively new and the fuel relay is upgraded as well. The tune is a custom cobb protune, and my car has the following mods:
AEM intake with K&N filter
UICP
DF catchcan
UR DP
ETS TP
Stock catback
3 port boost controller
also it pops up P2096 code (I believe it should be from the testpipe?)
What could possibly be the problem? Thank you so much for your help!

 

Either something is broken, lose, leaking
or
you need to go and have the MAF and MAP rescaled for driving.

Some tuners just focus on WOT, which that appears fine based on what your seeing. It's all the rest of the areas of the maps that take time to work out and make the car "locked in". You also shouldn't be popping that code since you have a TP.

 

I think the ltft was normal from what previous owner says. So what could possibly broken or leaking?

 

10% off is horrible.

LTFT range is ±12.5%.
STFT range is ±25%.

For instance : mine is +/- 2% most days. If there is a fast temperature swing outside I might see +/- 5% at most.
Since your problem is at cruise (not boost) it is MOST LIKELY a MAF/MAP cleanup issue.

 

I will clean up my maf tmr and see what happens after. I did took off some parts days before and sort of just left maf exposed.

 

The MAF airflow curve is what I was referring to. The tune needs to be cleaned up (most likely).

 

bump