I have a '00 2.5I Z3 with 148k. Idles ok when cold, but after it gets a little warm, has trouble finding idle. Surges up and down before settling in. Will die when you slow down from highway speeds. Throws the 1188/89 codes, which indicate a fuel problem. Thinking it may be either the Crankcase Ventilation Valve or the Idle Control Value. Any experience or advice?

Thanks..