Floating revs, air supply system modifications for the Audi 100 C4
When the engine was idling, I discovered a torn hose running from the idle air control valve (IAC) to the engine itself. It had torn more than once, and because it would expand and contract when changing the air supply, it would eventually crack. To prevent this from happening again, I decided to fix it and installed a metal tube inside. Now everything is running fine. 2.3L petrol engine, APR.