Stuttering on boost
 

1993 Classic turbo, import. when pressing on hitting 5K+ it starts to stutter and engine light comes on. After some less spirited driving the engine light goes out. I will drive the car and do the diagnostic 2moro but was wondering what the likely cause could be.
Knock sensor detecting knock then retarding the ignition?
Coil packs/Leads/Plugs breaking down?

The car has been chipped (was like it when the car was purchased) has a full 3" exhaust and -22 actuator. Could this sh7tty chip be the cause of the probs. The car runs 1.0 bar max.

I have looked on here about how to put the car into diagnostic mode and i believe its just a case of putting the two black connectors togther under the dash?

Any ideas much appreciated!

Best guess would be plugs first, then coil packs

it is showing up fault codes

24- idle air control solenoid
31- throttle position sensor
33- vehicle speed sensor
45- pressure sensor- pressure exchange solenoid valve

any ideas where to start looking to stop these fault codes appearing?