09 Mini Cooper S Manual.

Engine was replaced because the timing chain broke and oil starvation was a concern.

First shop that worked on it wasn't really qualified but since the dealership was paying for the repairs I foolishly let them use "Their guy" Their guy got frustrated with it and sent it to his buddy. Who knew more than the first but still was under qualified.

Got it back still had some issues to sort through. Finally after throwing just about every part at it I could I got all codes to clear.

It was running rough, best way to describe it is it ran lumpy. It ran like it had oversized cams. I narrowed it down to annair or vacuum leak by unplugging MAF and MAP. When the sensors are unplugged it runs beautifully. So I did a smoke test and found the intercooler inlet side was leaking. I replaced the intercooler with an OPL which is the cheap larger intercooler.

The engine will run beautiful for about 10 minutes and then it slowly goes back to lumpy. No codes show up, but if I unplug the MAF back to normal smooth running. The MAF was replaced with a Bosch. I've ordered a MAP just on the off chance that its that.

What am I missing?

If the turbo doesn't provide enough pressure will that cause the engine to run as if there was an air/vacuum leak?

 

My gut wants to say that the timing is off, especially if those two dude didn’t really know what they were doing

 

Search the threads for “MAF”. Not long ago there was a post with the same symptoms of improved running with MAF disconnected. Can’t recall the root cause. I want to say it was the throttle body.

Timing could well be off given you had Bozo and friends at work. However the symptoms don’t really add up. I would expect bad timing to present as consistent bad running.

 

I had considered timing but the fact that it runs fine with the MAF unplugged is whats puzzling. Also it does run good for a few minutes before going lumpy.

The search function on mobile is pretty bad. I've scrolled through a few pages and have yet to locate anything.

 

Sadly the search function blows canal water on NAM.

Consider using Google to search the 2nd Gen NAM forum. Can’t recall exactly how to do that, but Google should have an answer for that as well!