Zd30 revs on idle but not under load

[Slash2650]

Hey guys new to the forum, not sure but has prob been covered but I changed the glow plugs on my zd30 yesterday that was all fine tool it for a run no problem.

Went to drive it today and have no almost no acceleration and no boost, it revs fine in neutral but under load it takes ages to get up to speed.

Checked intercooler pipes all good can't see any splits in any vacume lines under the intercooler I took them off the throttle body when getting at the glow plugs but put them back on the same way it's got me stumped any thoughts on the problem?