Evo 8 misfire at 4000-5000rpm

[FluX]

My cousin bought an evo 8. When we got the car we chained oil, and done the general maintenance before starting it. We then took it out for a drive to see if everything was working and it was (except for the ayc). When we took it out for a second time it started to misfire when reaching 4000rpm. So we changed the coil packs to a upgraded set and changed the spark plugs but it has not changed a thing. We fitted a boost gauge to see if it building boost and it is, it builds to 10psi then the misfire occurs. When driving it you can tell its going to misfire as it feels sort of sluggish. Any ideas on what we should check next? Thanks.

We had a fault on the tps which is now gone after we adjusted it with the adjustment we made it is now running to 5000rpm and building 14psi of boost before misfiring.

No fault codes are appearing when misfire occours.

 

[Evo 10 mechanic]

Have you changed the mass sensor iv got a 8 bar in mine I’m running 500whp mine was misfiring now all good

 

[Whitwell.Mike]

Don't fire the parts cannon at her. You need a scan tool with live data to see what is going on. Is it a rich or lean miss etc, single or multiple cylinder miss.