My 2004 mini S hesitates around 2500 rpm. Tried driving on fwy but could not go faster than 50 mph.
At a full stop the car will quit 90% of the time unless I keep my foot on the gas to keep the rpm up

 

Start by checking your Air Filter, make sure it is clean and clear also check under the filter, make sure no critters climbed in and made a nest.

If that is all good, next step is checking your Fuel pressure at the fuel rail, being a 2004 you may need to replace your fuel filter/fuel pump.

Check those things and see what you find.

Motor On!

 

Fuel filter changed a few days ago with no improvement. Both air filters changed early last year. I did notice that if I really floor it while the engine is hesitating in 3 and 4th, almost to redline that seems to clear the hesitation. I don't know what the idle rpm are supposed to be, but presently it is idling 800 to 900. Initially when cold the tach will fluctuate between 900 and 1300. When fully warm it will hang around 8-900.

 

Manually turn off the DSC and see if that makes a difference.

 

Did you by any chance manipulate the intake boots or throttle body?

I would check air connections, PCV, fuel, and electrical connections again. R53 is known to cut some power between 2800ish to 3200ish... Aftermarket throttlebody with larger bore are meant to address this (but you end up with a twitchy throttle.

 

No, haven't opened the hood since Oct. '24. This is a non mod. vehicle.
I am wondering if the MAP would cause my issues?

 

Is the fuel pump original? Consider replacing it. They are not easy to test - other than pressure at the rail, but that might not tell you how it works under load. Any codes? No codes is another hint of the pump.

 

Original fuel pump. Code mentions MAP.
Would a dirty MAP cause all these issues?

 

The manifold absolute pressure sensor (MAP sensor) could be causing the issue, absolutely.

 

Will get back here with the update early next week.

 

If the code points to map, check the map

Your description of hesitation would make me check the crank pulley rubber core and the bypass valve as well. Both can cause hesitation and are easy to check.

 

Be aware there is a MAP and TMAP, one measures before and other after supercharger. What code is it throwing exactly?

Map issues on these cars can sometimes be a pain to find as any leak on the entire vacuum system can be culprit.

 

... and after 3 hours of diagnoses it turns out to be a bad O-Ring.

 

Both sensors replaced with oem parts, runs just great now. I'd forgotten I had the MAP sensor replaced last year from Napa but not the other and had less than 100 miles on it. So this German indy didn't want to warranty work with non oem parts and I didn't want to find another indy who would use whatever parts would work. Did cost me but at least she runs very well after 110k.