this is what solved the bump/clunk for me.... I believe it was a problem on trucks without the leveling suspension too...
The Bump/Clunk fix involves replacing output shaft and drive shaft yoke in the transfer case.
Technical Service Bulletin #07-04-17-001C: EI07148 - Bump/Thump Noise...
Prelude to window motor FAILURE !!!
depending on how many times you use it, it's ready to blow... had the exact symptom, motor quit within 10 days. Motor replaced, sounds just like new.
Sure you can do just about anything you want without effecting the MAF sensor. There is a 90 degree turn out of the engine then some more turns and bends to avoid the fan. I choose just to get the CAI from cold air inductions....
2005 - 2009 Saab 9-7X Intake System - 2008 - V8 5.3L - 9-7X -...
Just got back from a NY to VA round trip (900+ miles). I averaged about 75mph and got 18mpg with a well loaded vehicle. In the summer, with slightly slower speeds I got 20+.
I think the winter gas has an impact, just a gut feel.
I'm seeing the same thing with the cooler weather now but I do mostly local stop/go driving. I'll be doing some highway driving next week and see how that goes.
If you own a tuner, you could always flash the original stock settings back to the PCM/TCM, a couple days before going for warranty work. I know it's not 100% foolproof but would be much harder to detect, let alone prove.