Knocking noise and losing power

So we changed the oil cooler because there was no boost on the turbo. we changed the actuator. the pollution light was on from when I bought it so we replaced the EGR. but before the EGR replacement was driving and the engine just cut out on me managed to get it home and change the EGR. but after that the van is losing power thinking maybe that the catalytic converters blocked which they are sorting. today just dunno what the clunking noise is hoping it's not internal it sounds like metal on metal. but only happens sometimes when you rev and clutch isn't engaged, so it's not needing a new clutch.
Confused.com is an understatement.