scan starting and stopping

I have a 71 Chevelle with a 98 PCM/LS1 from a f body swapped in. I pulled the car out of storage today and wanted to scan the normal stuff.
Hooked up HP Tuners v2.24 connected, started scan. It will go for 4-6 frames then stop for a spklit second. Then scan for 4-6 frames and stop for a split second and on and on and on. Car did not do this last year when I stored it or ever. Car has a good battery 13.8v. No DTCs. Checked grounds seem ok.
Tried scanning two other vehicles (02 Taho and 01 Impala) and no scanning issues. Puter has a charged up battery not charging on car.
Any ideas are greatly appreciated