[beamerboosted08]

I have an 08 335i and i just put in new NGK 2 Step colder plugs 2 days ago due to the oe spec bosch plugs not holding up on high boost. Car has dci's, BMS aluminum chargepipe, catless dp's, dinan intercooler and oil cooler, alpina flash trans, no res no muffler, 3.5 bar tmap sensor, and i put in 6 new delphi coils 2 months ago around late july. Gapped the plugs to .022 and everything, car ran amazing for 2 days, then all of a sudden im racing this E92 335i on the highway and i get a combustion misfire cyl. 3. It was constant so if i gave it gas the car would shake and vibrate. Pulled off the highway into a parking lot, turned off the car, cleared codes, turned it back on and codes gone car drives fine until you go half throttle or more/ heavy load it misfires but no codes come up the car just vibrates like crazy until you let off which is what I did right away. I heard that if the coils go bad the car can misfire on heavy load, is this the same case? Car has a Stage 2+ MHD tune too btw. Could this be the ignition coils out due to high power output? Was wondering if anyone else had this problem and could help me out... This also happened before when i went from dinan stage 2 to mhd, but i swapped plugs and coils after i switched to mhd and it fixed it. So im thinking it could be the delphi coils.

[Buug959]

Ya found it!

[beamerboosted08]

Originally Posted by LemansE90335xi

Ya found it!

[OneShotOneKill11S]

Originally Posted by beamerboosted08

I have an 08 335i and i just put in new NGK 2 Step colder plugs 2 days ago due to the oe spec bosch plugs not holding up on high boost. Car has dci's, BMS aluminum chargepipe, catless dp's, dinan intercooler and oil cooler, alpina flash trans, no res no muffler, 3.5 bar tmap sensor, and i put in 6 new delphi coils 2 months ago around late july. Gapped the plugs to .022 and everything, car ran amazing for 2 days, then all of a sudden im racing this E92 335i on the highway and i get a combustion misfire cyl. 3. It was constant so if i gave it gas the car would shake and vibrate. Pulled off the highway into a parking lot, turned off the car, cleared codes, turned it back on and codes gone car drives fine until you go half throttle or more/ heavy load it misfires but no codes come up the car just vibrates like crazy until you let off which is what I did right away. I heard that if the coils go bad the car can misfire on heavy load, is this the same case? Car has a Stage 2+ MHD tune too btw. Could this be the ignition coils out due to high power output? Was wondering if anyone else had this problem and could help me out... This also happened before when i went from dinan stage 2 to mhd, but i swapped plugs and coils after i switched to mhd and it fixed it. So im thinking it could be the delphi coils.

If the problem started 2 days after changing plugs, the logical conclusion would be that it's the plugs. 2 step colder plugs gapped at .22 with pump gas, you're probably blowing out the spark and need to either close the gap a bit or switch to a hotter plug.

[beamerboosted08]

Originally Posted by OneShotOneKill11S

If the problem started 2 days after changing plugs, the logical conclusion would be that it's the plugs. 2 step colder plugs gapped at .22 with pump gas, you're probably blowing out the spark and need to either close the gap a bit or switch to a hotter plug.

Found the culprit. When it first happened I got a misfire code for cylinder 3. Popped the hood earlier today, pulled out the ignition coil, turns out the rubber insulator boot that goes on the plug literally broke and wasn't doing its job keeping the current from the coil going to the plug. Got an old coil that I had laying around, cut off the boot from it and makeshifted it onto the new coil pack that had the broken boot, and boom! Hitting huge numbers once again with absolutely no misfire issues. Thanks for the help though