Mk3 golf running bad pls help

[G mk3 golf]

I have mk3 golf 1.4 97 and its really bad on petrol and tickover bad went warm I have had new throttle body temp sensor ht leads plugs air filter and I got relay 167 and 30 but mine didn't have relay 30 ? And it's still bad ? Pls help

[Screech16v]

Has it been plugged in for a diagnostic  check ,lambda sensor?

[G mk3 golf]

Had it plug in and it come with idc so had new throttle body it made it bit better but not lot

[Screech16v]

My guess would have been lambda but that should have thrown a code, mmm

[G mk3 golf]

I have only had the car 3 weeks it looks new 2 me mate and it only come up with idc

[Screech16v]

So idc, isn't this a code for imoboliser fault?
EDIT,
what exactly does idc stand for? im not familiar with this abreaviation

[G mk3 golf]

Idle controll value mate

[vr6D4v3]

Isv then (idle stabilisation valve)