Yeah I agree. Put a load on it in gear and LTFT came down to 10 at least so definitely worse under vacuum. So probably a vacuum leak.
https://www.youtube.com/watch?v=QrO5k6a ... hristensen
Evidently the most common issue is the intake manifold bolts loosen up. However, this comment caught my eye:
So the current plan:I'm a heavy equipment diesel technician so this issue is never common place but own a 14 2.5 malibu. Had same issue twice now. Did some research to find this issue. Then one day at work met a guy who's uncle designed the 2.5 and 2.4 eco motors for gm. Me and him had a great talk let me tell you. The only way to resolve this problem it to remove the rubber gasket from factory and install a neoprene gasket. The rubber creates vibration and bolt will lossen up again. Since I did it's never lossened up again. The 2.5 pcvs need changed often. Don't forget to do that. You can blow a rear main seal. No good. The pipe that connects them has a downward loop which collects moisture. I haven't done this next step yet but will because it makes complete sense and the guy told me do this and I fully believe him. The pipes loop needs removed and install and straight hose with two shrink clamps on the ends. No more moisture build up. He's seen many many rear main seals blow because of this. " ". Ok ladies and gentlemen good luck.
- Look up torque and tightening sequence
- Tighten bolts (what is this, a Northstar?)
If it happens again I'll look into the neoprene gasket. His comment about the PCV also sounds like something I might want to do before something bad happens.
PCV info: https://www.youtube.com/watch?v=LYyMJA0 ... ovanFoster
I'll order both.