Unplugged my air con?

[checkpoint-direct.co.uk]

For the last few days the old motor has been hunting and idleing quite low.  Basically found that the clutch for the aircon would not disengauge so i unplugged it.  Eversince unplugging it it does not pop and bang on over run but shoots massive flames when it hits the rev limiter!  Never did that before.  Question is i can remember from my first rx an air pump that pumps air onto the cat does it work from the aircon pump?

Old car engine shown.

[MillSpeed]

That is your air pump. The air-con compressor is on the other side of the engine, undernearth the power steering pump.