Engine hesitation
 

Hello and I apologize if this is a duplicate query.

I have a 2005 R-52 base Cooper with 78k miles and auto trans. When I step on the gas, no matter whether at speed or from a stop light, there is a considerable lull before I get much throttle response, like you really have to consider whether you want to make a left turn at an intersection considerable lull. MPG sucks too. In Park standing still, throttle response is much better.

I bought the car last year and had the tranny service done by my local BMW dealer, thinking that might be the issue but it didn't really make a significant difference. I then changed plugs and wires, making an improvement on response and MPG. Recently I replaced the ignition coil and that made a difference as well, but it is still not really as it should be. (Plus I wonder if the coil should be mounted elsewhere, off the top of the engine heat.)

What else should I consider to improve throttle response?

TIA.

Curious, while you feel this poor throttle response, do you have the AC running at all?

It happens 100% of the time, AC or no AC.

To expand on my reply, regardless whether the a/c is on or off, the engine behaves like a two stroke. Very sluggish off idle until about 2600 rpm where it quickly comes to life and I have to roll off the throttle.

I wonder if there is a software issue; the throttle is drive-by-wire. If I open the throttle greatly, the engine doesn't get lively until close to 3000 rpm. But if I open the throttle less, the engine gets lively at a lower rpm. I could understand this better if there was a direct linkage to the intake butterflies which would let in too much air (affecting intake velocity), but a properly functioning electronically operated throttle shouldn't do that.