I've looked and looked for an answer on here but only more popping up with no answer to the problem...

So I put my car back to stock except for the piston's and it drove great for a slow, stock Mini S

When I accelerate thru the gear's it pull's good but at 30% throttle, it jerk's bad like it has a vacuum leak and upon decel the cardrop's in idle to 500rpm's and goes back up to norm, but if the a/c is on, the car dies completely...
Been to the dealer, paid their prices... Been to 2 local Mini Specialist mechanic's and no one has an answer...

!!!!!!!!HELP!!!!!!!!

 

How was our help?

 

Well with the sensor unplugged the car does not die or chuck at part throttle... Only once with the a/c on...
And on the way back home today from the shop, it drove the same. So Let's fix the head and than worry about the rest before any more damage....
Thanks Victor!