Hi guys,
This weekend again second time check engine appear on my car this time seem like it stays for good. but one thing I am about to tell you make you guys think i am smoking weed or so ... Start up the car then feel like a lot fluctuate on the RPM then the check engine appear but strange thing is when check engine turn on, the idle very smooth, no shaking, fluctuate at all. (Do I smoke weed ... Hell no.... ) Took the car to Auto zone to check. there is a error code P0304
definition is:
Cylinder # 4 misfire condition
Explanation:
Ignition system fault
Problem cause:
Plugge or faulty fuel injector
Vaccum leak
Engine mechanical condition

what I dont understand is sine check engine on the idle very smooth when start-up in the morning or late at night ( last night). Any comment feedback guys ?

 

Check the plugs and coils, switch the cylinders and see if the error goes with the plug.

 

I was experiencing similar with my car recently. I took it to a local BMW mechanic they ran a diagnostic and it stated that the Mass Air Flow (MAF) sensor was faulty. I got MAF cleaner, removed the MAF (careful not to touch the elements) and sprayed it about 15 times put it back in and the Service Engine light came off. It ran a lot smoother after.

Ray