R52 Stalling, backfire and poor fuel economy-Solved!!

[CJstem00]

So at around 90k started having these issues. Codes were intermittent and included bank 1 sensors, crank position sensor, and a couple others. Took it too a local shop here in Phoenix (Ken's Auto Repair) recommended by AZHitman (thanks dude!) For diagnosis and repair.
They found the air/fuel sensor was bad, a lower intake manifold leak and valve cover spark plugs seals leaking and lastly the crank pos sensor. Only cost $1000 to fix it all and she runs perfect. Mileage in mixed use is around 17.5 mpg, power is back and I am stoked again. Hope this helps someone with thier issues.