I have a 99 civic si which has recently developed a very nasty idling problem. I know this is a fairly common problem i just need some quick answers. My friend works at a dealership and did a full system scan on it. The iacv was malfunctioning and the engine load was kinda high (think thats the plug wires?). Anyway i recently tried to install an air/fuel gauge and was wondering if tapping into the o2 sensor sending unit line may have caused the problem. I really don't want to spend the money on a new iacv if i don't have to. Any suggestions, tips, etc.