2002 R53, 245K miles, burns lots of oil. Driving to work this morning I get an engine miss and massive power loss. Codes P0326, P0302 and P0300. I was able to limp back home, but just barely. Two weeks ago, the P0326 appeared, but went away. It's back, with the cylinder misfire. Could the failure of the knock sensor cause such a huge power loss? I'll replace it but am concerned something else is going on. Oh, and thanks BMW for burying the sensor under the SC!! I've replace the SC oil in the past, so I know how to get to the sensor, but sheesh. Now I'm wondering what else I should replace while I'm in that deep.

 

P0326 - Knock sensor (KS) 1, bank 1 – range/performance problem
P0302 - Cylinder 2 misfire
P0300 - Random/multiple cylinder(s) – misfire detected

You said you're burning lots of oil, so the first things that should be checked are plugs and wires. If you find oil in the plug tube, look at replacing the valve cover gasket and plug rings. After that, check the injector, injector connector, and wiring for cylinder 2. Put a bottle of Lucas in the gas tank for kicks... if you're going to investigate the knock sensor, it'll be the perfect time to check the injector.

Good read for your issue.

 

Plugs and wires are only 20K miles old. Replaced coil pack last night, with no joy. Pulled cyl 1 plug and it's very oily looking. After clearing codes and starting engine, P0300 came back and engine is still barely running. Very rich smelling exhaust too.

 

I'd replace your valve cover gasket and plug rings. Should clear up your oil burning issue. Running rich and misfires can be explained because the plugs are drowning in oil and not igniting the fuel.

 

There's no oil in the plug wells. I had the head off 20-25K miles ago so all the head gaskets and seals are new. The oil on the #1 plug is around the electrode.

 

One more piece of info that might help diagnosing this. When it happened, it was sudden. I was at highway speed and had an abrupt loss of power. I was able to keep going, but foot to the floor to keep at 60mph. Hills and stops were difficult, but I limped home with the engine running like crap.

 

Fuel pressure is about 50psi, but after doing a compression check I found zero psi in Cyl 1 and 4. Pulled the head and found a burned/broken exhaust valve in each of the two bad cylinders! How is it possible to burn two valves simultaneously????