[Charmadize]

I would only guess at a small leak in the pipe work from the turbo through the intercoolers.
Can you rig up a pressure test through the pipe work to the throttle?
It sounds like you've had a few problems, so hopefully this is just the last one.
Do you still get the misfire error as well? Even though you've replaced the coil?

 

[Charmadize]

I would only guess at a small leak in the pipe work from the turbo through the intercoolers.
Can you rig up a pressure test through the pipe work to the throttle?
It sounds like you've had a few problems, so hopefully this is just the last one.
Do you still get the misfire error as well? Even though you've replaced the coil?

Yes I still get the misfire errors. I've not done a pressure test... honestly not sure how to do that. Could you link me to whatever product you use? I can probably figure out how to do a pressure test from there

Sorry, didn't check in yesterday. There is no kit for this, you will have to Jerry-rig/Heath Robinson something together to test the circuit.

Before I start, you might not want to progress with this because it is a real arse!

First stage is to pressure test. You will need to disconnect the pipe from the turbo and the inlet. Then you will need two solid circular items and a jubilee clips to block off the ends you have disconnected. I have used bearing press kit for this before, which worked well. Then use one of the off take pipes for the valves, and plumb in the valve from a compressor ideally. If you haven't got one of those, you can use a foot pump. Clamp the pump valve into the off-take using another piece of rubber tubing.

Pump a load of air in and leave it for a bit. If the pressure doesn't drop, there isn't a leak.
If it does drop, then you are into the realms of taking the air circuit out and test each component in water and compressed air in a similar way.

Sorry, it isn't a straightforward solution.

 

[Charmadize]

As you've replaced a lot of the intake (air) system, then it points now at the fuelling, maybe?

Before we go down that route, the cross member that joins the intercoolers get very rusty abs on mine, I was worried that it was close to rusting through so I replaced it.

If that is ok, then the misfires could be from lack of fuel in the chamber. The cat issues could be because the firing is so lean, due to lack of fuel. So, I think next you need to check the fuelling and the injectors. Have you looked at these already?