Well the XF almost left me stranded tonight. It tried to stall in the middle of the road when I was giving it some throttle turning at a green light. It missed really hard and almost died... but ran good enough to pull over/coast into a gas station and park. The car started bucking and going crazy and the CEL and Battery Light came on.

Oddly enough, the car cranks up just fine and all the lights work, a/c, radio etc, but when you try and rev up the car just a little in either neutral or park, it hesitates really bad and wants to stall. None of the lights dim when this happens though. If you try and drive it and take off too fast it will stall and the battery light will come on. It wouldn't crank for about 10 seconds, no clicking or anything, then it would slowly turn over things will go dim and then turn on. My battery is cracked on the top and corrodes pretty bad. Luckily I was able to slowly drive home. When your light on the throttle and go at a steady speed it's just fine.

I'm not thinking this is related to any of the no start issues (crank position sensor, fuel pump relay, modules etc) since it cranks just fine. I just wanted to make sure I'm not overlooking something, since my girlfriends mom has an SLK320 and has tons of the same problems. She said she thinks it sounds more like when her module went bad and it's not the battery.

Sadly I just payed almost $100 having the car looked at and they said it's just fine, it's been throwing no codes until tonight. The car has been having hesitation after it heats up and power surging when going with traffic (another post I made). The mechanic said I was getting unmetered air at the MAF and I just needed to tightened my intake. I'm thinking this is the problem I've been dealing with all along.

I'm getting a ride to work tomorrow then I'll be able to look more into things, any help at all would be much appreciated.