I have a 2007 Cooper non S. Blew a head gasket. Changed head gasket. Head is fine. Reassembled. Timing is dead on. Cleaned throttle body. Cleaned vanos solenoids and cam position sensors. ECM is not throwing any codes. Car started fine took it for a drive about 30km. Ran great. Took it home in the garage drained oil and coolant. Replaced both. Now the car will start but the idle is up and down. Engine shakes. When the gas pedal is depressed the RPMs surge up and down while the gas pedal is held in the same place. Please someone chime in here. I'm getting fed up with this car lol.

 

Check engine oil level and be sure that it isn't overfilled. If overfilled, it can foul plugs and result some symptoms you described. Give the plugs and coils a good check.

 

the car needs a cycle of about 30 or more miles to through back codes. check the above mentioned and drive the car until you get codes. It could be as simple as vacuum leak or unmetered air flow. Also, the car is trying to learn the new values. does it behave differently when warmer than cold?

 

It's undriveable right now. I will check the oil and check the plugs tomorrow. I'll post back if it helps.

 

When you changed the head gasket did you send the head to a machine shop? Or did you eye ball it and assume it was fine? If its running that shitty the codes should't need that much of a drive to come back. Did you actually scan for codes or just no light on?

 

Sounds like a vacuum leak, perhaps?

Check the dipstick, all the PCV connections, boost couplers, etc.

 

It does sound like an air leak. Before doing anything buy some brake spray start the car and spray all over the intake manifold any air tubes etc if the car shudders theres an air leak there.