V70 threw a CEL so I had my software upgrade to the throttlebody. The code, ECU 644 camshaft control, was entered only once and apparently some time before the CEL. Ok, so they cleared the code, updated the s/w and I drove on. All was well for 3 days when another CEL. No performance problems except that mpg seemed to drop slightly. Stayed lit for 3 days until after I called the dealer and scheduled an appointment, when, poof the CEL goes out. Dealer service rep is now silent. <p>Has anone heard of such a thing? Disappearing CEL or mpg reduction?