Rough Idle, Lag Or Surge In And Out Of V4 Mode 07 Vmax

[pubenemy]

Hello I have an 07 gmc sierra vortec max that has a rough idle, also it started some sort of surge or lag coming in and out of v4 mode recently. I never used to notice it coming in and out of v4 mode, now its very noticeable. I've had a bad history with this truck so far. All the forward gears went out in the tranny once, and the left side lifter banks have collapsed 3 times. Ever since it never idled right. Problem is now I am out of bumper to bumper warranty and worried about these issues not being covered under drivetrain warranty. I have an 06 vmax also that Ive not had a single issue with. Also ever since the lifter banks issues the oil pressure is lower. When the lifter banks collapsed the truck was sort of driveable but was blowing a ton of smoke and oil out the tail pipe and ran real rough I of course parked it and had it towed. Any ideas of what these issues may be and if so covered under the 100k drivetrain warranty. I use this truck for work and drive 250-3500 miles a day it needs to be reliable. Im getting worried and wondering if I should dump it and take the loss(upside down) on it and trade it in. Seems like a lemon as my 06 hasnt had a single problem. Any input by anyone would be appreciated.

Thanks

-Mike