Have had my '00 E39 M5 for about 3 weeks now. When I first bought it it was lightning quick in lower gears with minimal throttle. In the past week or so the acceleration has gotten noticeably worse, to the point where in 1st and 2nd, especially, the car seems to just really be lagging. Coming off of stop lights w/ Sport Mode on I'm working hard to stay nose-and-nose w/ Grandmas in vans? No misfires, no SES lights, no other engine noises, just much slower. Idle seems fine, no rev-hunting. Wednesday night I took out the MAFs and sprayed them down thoroughly with some CRC MAF cleaner (per instructions on the can), and didn't notice much change. I have the instructions for testing MAFs, just haven't done it yet. I have an aftermarket warranty, supposedly covering everything but the wear items (brakes, clutch, wipers, etc), but for a $200 deductible, I was wondering if it's possibly anything I can check myself. Plan on checking MAFs today or Saturday... Any input appreciated, thanks.