P0601 Internal Control Module Memory Check Sum Error???
EML light was on. Got it home, it did start, but ran very poorly. It sounded like a vacuum leak from towards the front of the intake manifold area, but under. It's running, not too bad, but not happy. I'm kind of pulling on this and that to see if I can find anything, pulled lead off the AMM and it hickuped then ran about the same, maybe a touch better, maybe not. Plugged it back in and it did the same. I'm leaning and listening to things and all of the sudden it cleared up. Hissing noise nearly completely went away, ran nice and smooth, rev'd quick and clean up high. So I scanned it and came up with P0601, P0443 which is Evaporative Emission System Purge Control Valve Circuit and has been coming and going for a while, and a pending P0304 which is cylinder 4 misfire.
Car had been running perfectly since I did the Vanos rebuild a year ago, no hickups, nothing odd, 20K miles and getting 25-26MPG. Any thoughts?