Bought a 2nd hand 2009 hatchback non S 55k miles, decided to change spark plugs/ ignition coils (plugs - NGK ILKBR7B8DG / 95770 & ignition coil - Delphi GN10328). *Search the forums and websites to ensure they were suitable replacements, bought off Amazon for about $150.

Before replacing the plugs and coil packs, there was a check engine light and P300,01,02,03,04 OBD codes and engine would intermittently engine stall at idle/coming to a stop. Troubleshooting and swapped spark plugs and coil packs around and the codes still remain. Did the seafoam thru intake vacuum and surprisingly the faults went away and no more rough idle/engine stalling. Been running the car 2 weeks now, refilled gas once with no engine stalls or rough idle.

When removing the original Beru plugs, noticed they all were fouled and the center electrode looked worn down. Replaced all spark plugs and coil packs, the Delphi coil packs were a little snug and hard to push down and some resistance / hard to make them seat.. not sure if they are suppose to be that way. Started the Mini up and right of the back again intermittently the idle was rough / pulsing in park and engine stall, you can hear the computer try to compensate and then after awhile the rough idle will return. Took it for a spin around the block and same rough idle symptom. Decide to re-install all 4 original coil packs and now the rough idle problem cut down by half / 50%, but still it will come back intermittently when I start up. The bad part is there is no check engine light so no codes to refer too. I plan to drive around for a little while to see if any check engine light / fault codes pop up. Perhaps later for more troubleshooting I will re-install the original spark plugs and install the new coil packs?

I cannot see how both new spark plugs and ignition packs can be bad. I've done general car maintenance in the past and i don't see any physical defects with the new parts. Any suggestions?

 

Check for vacuum leak. Possibly do a Compression Test

 

Try putting the old coils back on and test again. If the car ran ok before you replaced parts try going back and putting the OEM parts back on.

This could be a aftermarket part issue you can’t see. MINI’s are picky when using non OEM electrical parts. Coils, plugs, Batteries without registration, O2 sensors.

 

+1 would have to agree with post above. If the vehicle ran fine with the original OEM parts and after the sea foam cleaning then your aftermarket parts are probably more of the problem. I would suspect that he coils off of amazon is the culprit. Get a set of new original coils and go from there.

 

found the PCV vacuum line loose, after securing it.. the idle ran better. Thanks for the suggestion

 

So like i mentioned earlier, found the PCV vacuum line loose and after the idle got better. Put back the original spark plugs and coil packs and now everything runs ok. Even if the coil packs are OEM listed, they felt tight and didn't sit right to me. Decided to return the NDK plugs and coil pack and re-order a set of Beru plugs.