Hi, thank you all in advance.

I have a 02 MC 150000kms. couple of weeks ago fuel was low and I stopped at a gas station and put premium fuel. I started driving and my engine light came on. I took it in to my cousin who is a mechanic and the code was P0303. We replaced coil, swaped wires and spark plugs and code was still same. He did engine compression test and was over 150 on cylinder #3. He checked the oxygen sensors with good readings. My car has no driving problems, I dont notice anything out of the ordinary. I've done a lot of reading in different forums with same problems ppl have but no one mentions the solution to the problem. If anyone can help I would really appreciate it. Thanks again. I forgot to mention asc light comes and goes. Today I started the car really cold and engine light and asc was off but after driving for 10 mins the lights came on. I just wanna know if this has to do with sensors or engine. Soo many peopel mention map sensor, 02 sensor, fuel pump, ecu, throttle body. Please help in any way. Thanks again.

 

Thanks everyone for not helping me...I ended up finding the problem on my own. I was about to take the head off but just before doing that I got a seafoam can and did the treatment. A day after the treatment the lights turned off and no more misfires. If you have same symptoms as mine start with seafoam as it is a cheap, easy and will not harm your vehicle. Good luck to all.

 

Congrats....good to hear it was pretty simple....and now your car has been freshened a bit, so all is not lost!! I wish you many miles of happy motoring!!
SeaFoam has proven itself to be pretty amazing stuff when used in a MINI!!

 

relax ; most posts take a day or two for any real feedback . glad you fixed it and thanks for sharing

 

Mine was having the same kind of issue. Replaced coil, wires, plugs, o2 sensors, seafoamed. Still throwing codes....worse than ever actually. Only thing I can think of is the IAT sensor. I just haven't gotten around to locating it in the engine bay and replacing it.