Yes the truck was retuned after the intake install. A cai was installed at the same time. The afr is between 12.6 and 12.8. On target with what i was commanding.

 

x2

My L31 started doing something similar and it was tired weak valve springs allowing valve float.

What kind of springs are you running and what is the seat and open pressure?

Also how much lift on that cam?

 

I was gonna say valve float

 

X2 valves springs need upgrade.

 

I also just want to point out that once the valves are floated a few times, the springs will progressively get weaker and weaker. So noticing the issue more after tuning the 2nd intake would make sense that it likely is valve float. Even a good running engine will see slight MAF variations (5-10 gm/sec between frames) but if it is large spikes it is almost certainly valve float.