Check Engine Light - P0304
#1
Check Engine Light - P0304
All, Today my amber check engine light came on, and engine began running rough - same time I was accelerating to enter the freeway.
Later I stopped at the car parts store and had the code read by the tech as P0304. Mini is one-owner 2012 Cooper S with 56,000 miles and was under extended factory warranty until last year, so all factory maintenance should be up to date.
Now for the puzzler...
I always use premium fuel in my Mini, but about 2 days ago I stopped at a gas station I don't normally use and accidentally tanked up with regular. This might mean nothing?? So later today I bought some octane booster and added it to the fuel, didn't make any difference to the light or improve drive-ability.
Where to go from here?
a) Should I swap coils between cylinders 3 & 4 and check to see if the code changes?
b) Could I have a tank of bad gas? should I have it drained, and change the filters? How could I test this theory?
Any assistance is appreciated, Thanks.
Later I stopped at the car parts store and had the code read by the tech as P0304. Mini is one-owner 2012 Cooper S with 56,000 miles and was under extended factory warranty until last year, so all factory maintenance should be up to date.
Now for the puzzler...
I always use premium fuel in my Mini, but about 2 days ago I stopped at a gas station I don't normally use and accidentally tanked up with regular. This might mean nothing?? So later today I bought some octane booster and added it to the fuel, didn't make any difference to the light or improve drive-ability.
Where to go from here?
a) Should I swap coils between cylinders 3 & 4 and check to see if the code changes?
b) Could I have a tank of bad gas? should I have it drained, and change the filters? How could I test this theory?
Any assistance is appreciated, Thanks.
#3
Appreciate the response. I swapped the coils between 3 & 4, still ran rough, but the code changed to P0303, so starting to look electrical. First bought new plugs, all were pretty worn and need of change. #3 plug was wet when pulled. After changing plugs still ran rough, so i bought a new coil and changed it out on #3 and all is good now. I'm guessing I saved myself a few few bucks by doing this myself, plus the satisfaction of man over machine.
Thanks for the help, Joe.
Thanks for the help, Joe.
#6
Can anyone explain why my R52 will start on the second crank even when it’s been sitting overnight in 20 F weather but I can go in a store for 15 min, come out and it won’t hit a lick after 5-10 seconds of cranking? Turn it off and then it will start right up. Always starts right away when it has been sitting overnight. Hit and miss when it’s hot. Lots of quirks to these vehicles.
#7
Appreciate the response. I swapped the coils between 3 & 4, still ran rough, but the code changed to P0303, so starting to look electrical. First bought new plugs, all were pretty worn and need of change. #3 plug was wet when pulled. After changing plugs still ran rough, so i bought a new coil and changed it out on #3 and all is good now. I'm guessing I saved myself a few few bucks by doing this myself, plus the satisfaction of man over machine.
Thanks for the help, Joe.
Thanks for the help, Joe.
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#9
Can anyone explain why my R52 will start on the second crank even when it’s been sitting overnight in 20 F weather but I can go in a store for 15 min, come out and it won’t hit a lick after 5-10 seconds of cranking? Turn it off and then it will start right up. Always starts right away when it has been sitting overnight. Hit and miss when it’s hot. Lots of quirks to these vehicles.
It's a leftover technique from the original cars that had an SU fuel pump in the boot (trunk!). Once the click-click-click stopped you knew the carburettor bowls were full.
#10
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