Eddie Jones says he is bringing in outside help in an attempt to solve what he sees as England's inability to cope with pressure.
England ended their Six Nations campaign with a dramatic 38-38 draw with Scotland at Twickenham on Saturday, which saw them collapse having led 31-0 just before half-time.
Jones' side also threw away a lead against eventual Grand Slam winners Wales earlier in the tournament, as well as doing so twice on their tour of South Africa last summer.
Jones believes England's problems are mental, and date back to the disastrous 2015 World Cup, when they went out in the pool stage despite hosting the tournament.
Asked why England keep throwing away leads, he said: "It's about how the team thinks under pressure. It's like we have some hand grenades in the back of a Jeep and sometimes they go off when there's a lot of pressure. We have a few of them and we've got to get rid of them.
"The team has probably had it since the 2015 World Cup and we've been working on a process to fix it. We will get it right, but it takes time.
"Whenever you have a difficult tournament or difficult games, there's always a lingering thought process there. Sometimes it takes longer than you'd like to fix it, but it is fixable.
"It comes in when you get under pressure, a lot of pressure, and you can't work out a way to get back to what you want to do.
"When we won 18 games in a row, we still had those problems. They have come to the fore in a couple of games recently which is beneficial for us because it's made it quite clear what we have to fix to be the best team in the world."
When pressed on how he planned to solve the issues, Jones said: "I've got one person that's going to help us that's a bit of an expert. I'm not sharing that name with you now. I haven't used her before."