Hello guys, I have a m42b18 engine, and I'm expieriencing some idle problem. The thing is, that i've checked everything that I could possible check, sparks are new, all filters are new, oil changed recently, head gasket w/ seals etc.etc. have been changed, ICV has been cleaned as well, but still idle remains shitty all the god damn time. I don't know what to do. I'm desperate. I've checked all the vacuum leaks n stuff, but yet I don't know where to look for a problem. Only thing that I haven't changed recently is O2 sensor. Can i check it somehow, with a diagnostic software ( i got delphi software). Perhaps some readings in diagnostics will give me an answer? What the readings should be for lamda as a default?