First gear pulls hard, then in second gear the car pulls at first then feels like it isn't going anywhere.

The weird thing is...the problem only happens in second gear, and it doesn't happen all the time...more times than not though.

For the past month the Autometer AF gauge has been stuck at the last green bar. Could the O2 sensor be bad (I'm not getting any engine codes)? I think that this happened around the same time the car started running bad.

Does anyone have any ideas?

Here's the setup:
B18C1
550cc inj.
EFI PMS