My 2002 E55 seems to be almost tempermental when it comes to acceleration. When I first took a test drive I was blown away by the "neck snap" acceleration. But my car seems to be inconsistent. Sometimes it accelerates relatively slowly and steadily from a standing stop--other times, something seems to just kick in and I get the "neck snap" I recall so fondly from the test drive. Same thing when I stomp the pedal when the car is already at speed: sometimes there's a brief hesitation, then wham! Other times just a steady but relatively uninspiring acceleration you'd expect in an Acura sedan, not an E55.

Any ideas?

 

Its the adaptive tranny. If you're just tooling around, it won't downshift or accelerate hard cause it thinks you're just tooling around. What you should do is floor it till it hits the switch on the gas pedal that signals the tranny to go into beast mode.

 

More likely to be a faulty mass fow air sensor, given the symptoms you describe

 

I have an 02 E55, try driving it hard for a couple of minutes, let the revs get up a little. Then try it from the line and roll on, it should perk up for you. Mine will get lethargic if I treat it too nice, kind of like a woman in that respect.