[See5]

Unlike most of you in the section my car is completely bone stock. I was going to change that soon but life got in the way as well as this random problem.

Every once in awhile under light throttle loads ie going up a hill on the highway at 60-70mph, the car will judder for about 2 seconds, at least enough for me notice the tach needle move with the event. Sometimes it happens while passing as well. It will then drive like nothing happened. Never had any problems at WOT.

I have an appointment with the dealer as the car is still under CPO warranty but the only problem is that it has never set off any visible CELs and is almost totally random. Without the codes, it just seems like there will be high probability that they tell me to go home and run some fuel system cleaner.

The car currently has 54K on it. I bought it at 44K but didn't know if any of the ignition system had any previous work done to it. They replaced the valve cover gasket at 50K along with the LPFP. Maybe some oil had previously leaked down to the plugs? Coils, plugs, and injectors typically have different symptoms but what are they for this platform in owner's experiences?

[enrita]

try to take off the plugs and see how they look.

[JamesM3M5]

Take the shotgun blast approach: New plugs, new pre-cat O2 sensors, clean intake ports, clean MAP sensors. I had to track down a similar low load misfire issue as well, did all that with injectors, too, but they didn't help much. At least not enough to justify $700 in parts alone. The things that helped the most were the pre cat O2 sensors and cleaning the MAP sensors.

[Mike@N54Tuning.com]

Originally Posted by enrita

try to take off the plugs and see how they look.

+1 or just change them. The service interval BMW recommends on these plugs is ridiculous.

Mike