'04 Mini S w/ 109K. Driving home from work car suddenly developed a misfire, went into limp mode. Car was running great, cruising at about 70mph then suddenly developed the misfire. Flashed the computer with code reader, showing P0301 - misfire #1 cyl. New plugs / new wires /new ignition coil problem still present. Checked the injectors, everything appears to be OK, all spraying. Swapped the #3 and #1 fuel injectors to see if misfire moved to # 3. No change so do not believe it's a faulty injector.

While it's not showing a P0345 code - faulty cam position sensor - anyone have any experience where this created a similar issue? Thought process here is faulty cam position sensor is telling the ECU to fire the ingition and / or injector out of sequence, thus causing the bad misfire and sending it into limp mode.

Just seems like it is something more along these lines than a more severe valve train failure with the way the problem developed. Hate to think about this, but other real possibilites in my mind is a burnt exhaust valve, worn camshaft lobe...... an thoughts / experience out there along those lines? Hate to think that that is what happen, especially given that everything has been great, no indications of any issues leading to this and the sudden development of the misfire.

Guess a compression test/leak down test is in order? Any experiences or thoughts on this would be greatly appreciated.

 

Seeing how you did some of the basics already the leakdown and compression test will narrow it down. MINI's are known to burn up exhaust valve guides. Good luck.

 

Yup...on the compression/leakdown.
No on throwing random parts at it "thinking" it might help...

 

I'm going to assume you attempted to clear the thrown code and it re-appeared. Did you "read" the #1 plug compared to the others? Observe any difference?

 

Thank you all for the insight. Off we go to check compression / leak down and confirm what it most likely is......exhaust valve issues.

 

Good luck. Keep in mind it is cheaper to get a new rebuilt head then use the dealer. They can be 3 times the price.

 

Braminator.....already there. Must easier and cost effective to bolt on a reman. head and move on. Already on the hunt for one in the likely event that it's needed. Have any personal experience / input on where to buy a good reman. head ?

 

I highly recommend them for service and price http://www.headsonly.com/

 

I had the same thing happen to me in a 06 jcw . Did everything u done. Same codes came up misfire cylinder. Lite came on in side and then it would flash. Ended up taking of head , there was the problem , when we spun the cam , there was a spot on the cam lop that the Harding of steel was bad. Replaced cam and all parts to related to number one valve . Put back together . He haw , works like a top , thank f...........

 

damccord, sending you a PM.

 

What PM

 

Same symptoms on my 05 R53. Pulled valve cover, broke valve spring. Leave the head on, fill the cylinder with cord, compress, change spring. All is well.

 

Certain, glad you fixed yours. Now motor on.