OK, read this entire thread...why? My turbo is moaning AND a CEL with flashing cruise light...you know what the code was? well, i'll tell you, AVCS timing issue...recommend checking oil to solenoid (the BB screen). Now, i've put 25k on this car, a DD, all highway bought it with 80k miles, changed oil every 3-3.5k using whatever's on sale. no synthetics as i won't waste synthetic every 3k miles. Oil always looked clean, i think IIRC. Oh, and as far as usage, normal, highway driving and cooldowns. i love this car, it's babied mostly and get on it when needed. If gas was cheaper i'd be on it more, for sure.
Now, here's the interesting part. the last two changes were with NAPA oil. supposedly made by valvoline. I find it ironic both problems may involve these screens at the same time after i started using NAPA oil. The root cause is as yet to be determined...updates to follow