Subaru 2006 loss of boost at 4K

[Wolfy]

When hitting 4000rpm in second I occasionally lose boost for a split second.. sometimes happens in first. It's completely random and doesn't always happen. Fuel cut or boost leak maybe? Or mapping issue?

[kayzarh]

is this all during full throttle? does the boost come back on after 4000rpm? do you have a boost gauge?

[Wolfy]

Under full throttle, it goes for split second then I have boost again. Yeah, I do 

[Wolfy]

Just in case anyone comes across this, it turned out to be the lamber sensor. I was quoted £350, so I recommend you do it yourself as it's like a half hour job, if that if you're more knowledgeable with cars. If I remember correctly, I paid £120 then like £15 for the tool.

Drove around the block, the car ran smoother, idled lower and pulled much better. I am, however, having issues with launching the car. It's not top of my list to sort since I rarely do it, but I will update this when I know the issue