hesitation and sputtering, cant figure out what it is any opinions? Options

[easternpiro1]

Hi all! i have been having an ongoing problem with my swap when driving. I get a weird hesitation/sputtering when trying to accelerate.

the problem happens more when im on the highway at a steady cruise, my AFR goes blank (reads ---) and car hesitates/sputters. when i get on the gas it stops.

after recently having the car sit for about 9 days i started her up and took it for a drive, upon initial acceleration (1st and 2nd gear) car sputtered and hesitated real bad, but after the car was driven for a while it pretty much stopped. its rough initially then smooths out when car is warmed up.

any ideas as to why this may be happening would be appreciated!

car is running on stock waste gate pressure at the moment (8psi) IC piping seems to be ok... could it be a fueling issue? it may be leaning out. Cam (boosted185) says I just need to tune it as the pistons are SLIGHTLY larger than stock pistons when he rebuilt the motor.