2009 135I Coil Packs

[onefastsvt]

I changed out my spark plugs with OEM BMW plugs today @40,000 miles. The car is idling rough when cold (seems to be ok once warm) so I assumed it was the plugs needing service. I noticed 2 of the coil packs had a white residue present (I should have taken a pic but too late now). After restarting the car its still having the same cold idle issue. Once warm it runs fine. I have gone to limp mode a few times after WOT runs and have had a check engine light that after clearing the codes never returned. Is it time to start changing out coil packs? (I marked the cylinders with the residue) I will run the plugs for a few days and post any codes that pop up post spark plug change.

The car was upgrade to the IS package and JB4 tuner running Map 5.

[Mr Rooty Von Tooty]

The coil packs either are OK or not. It's pointless to replace things that are still working.

You can easily check the coil packs with this simple method, there are others:

[mr.fabulous]

re-seat all the connectors

[onefastsvt]

Originally Posted by Mr Rooty Von Tooty

The coil packs either are OK or not. It's pointless to replace things that are still working.

You can easily check the coil packs with this simple method, there are others:

As it turns out there can be intermittent issues with the coil pack/s. My #3 cylinder ended up being the culprit but only had issues when cold. I replaced the coil pack and viola no more issue. I finally threw a code the day the packs arrived leading me to the bad pack but it never did not totally failed.