Hi all, I've bought an impreza from a friend that's got an issue, it's a low mileage standard bug eye wrx. it stood for a couple of years and it developed from there! It won't rev up from idle, it tries but it chuggs and backfires in the exhaust and inlet manifold. Now six years later it's time to repair the problem. I'm a time served mechanic and it's got me stumped, before I bought it it went to a garage for repair but they couldn't fix it either. I will list. New battery New timing belt New plugs All coils work ok and all 4 are brand new Replacement uppipe cat delete Recon turbo New fuel filter New fuel tank was drained New crank sensor New cam sensor Brake servo vacuum capped off. New Denso maf/mas Removed the exhaust just in case it was blocked Ecu replaced Fuel pressure at 40psi Return fuel pressure 10psi All cylinders are 140psi All live readings look OK and no eml warnings. No air leaks, smoke tested. 40kpa on idle All injectors checked, Removed and tested Removed and cleaned earth's Fuel trims are indicating running rich. I haven't removed the fuel pump to check the tea bag filter but I've got 40psi at the engine. What am I missing?