Norwich have won just twice on their Premier League travels this season, with only Cardiff City having fared worse on the road.
That has left Chris Hughton's side heavily reliant on their form at Carrow Road, where 24 of their 32 points have been won.
Tettey, who has played 16 league games this season, finds it hard to understand the stark disparity but is keen to redress the balance in the remainder of the campaign.
"I don't know what’s going on – but there is something going on," the Norwegian told the Pink'Un.
"I don't know what happens when we play at home. All of a sudden we have confidence – even though the last game was a horrible performance.
"We didn't know what we were doing at Southampton [lost 4-2]. But all of a sudden, it's all forgotten and we then played like we were in the middle of the table and we were safe [against Sunderland].
"So there is something I think mentally going on that we have to get rid of, because if we can win away from home and win at home, everything will be fine.
"To do that is much easier to sort out off the back of a win, because when you don't win away you have pressure on you to produce at home as well."
Norwich travel to Swansea City this weekend, and also face trips to Fulham, Manchester United and Chelsea before the end of the season.