I'm not a mechanic mate, sorry. I have seen your car some years ago and went around to the former owner Chris, hooked up my Opcom to check for faults, changed the split diaphragm on his recirc valve and replaced some vac lines if i remember well as it ran like crap with boost issues. Car did run well after that. She is getting older so I'd also check wires as these are prone to cracking. There is also a post one here about poor earth connection on the wiring loom , check that out too. Hope you get it sorted mate.