[hotwired78]

Guys,

I'd like you to read through and let me know if what I am feeling is normal behavior...

I had an intermittently rough idle after changing spark plugs and a new valve cover 1 month ago. I read somewhere that resetting all my adaptations might help via JB4. I will list the steps taken:

1. Reset Adaptations via JB4

- Caused Misfire in cylinder 2 and 3

2. Reset Adaptations again via JB4 and running the car for 10 minutes at 2500 RPM.

- Caused Misfire in cylinder 2 and 3

3. Swap spark plugs with old plugs in cylinder 2 and 3

- Misfire in cylinder 2 and 3 not resolved

4. Swap coils from 4 and 5 to 2 and 3.

- Misfires did not move

5. Took car to BMW to run diagnostic

- Caused a hole in my wallet for useless advice. SA stated: procedures would not let them continue testing and diagnosing without trying to replace ALL ignition coils first for 900 dollars quoted.
- I said hell no and bought 2 plugs from the dealership and replaced the in the service lane to prove a point.

6. Replaced ignition coils for 2 and 3 only so BMW could continue diagnoising

- Misfire in cylinder 2 and 3

- When placing hand on the ignition coil with the engine on, you can feel the knocking on the coil

7. BMW dealership tells me injectors are bad and they can smell wet fuel on the injector tip. - BMW forces me to replace all 6 injectors for a discounted rate of 1550.

- Misfires are resolved. Car runs clean

8. Took car to solo motorsports to have intake valves walnut blasted

- No noticable change in driving behavior. Can still detect intermittent idle change (+/- 100rpms)

- Cannot hear any misfiring or knocking. but when placing hand on coil #2, you can feel knocking. Cannot detect same feeling on any other coil.

Is it normal to be able to feel some knock on coil #2??? Did the misfires cause a permanent engine knock??? Bad valve springs? Lifters?

Thanks for reading

[JamesM3M5]

That's not knock you're feeling through the coil. It might be a lifter, but they tick loudly when they're bad.

A lot of times the dealer or previous shop has replaced one or more injectors, and they forget the damn decoupler element (spacer). This allows the injector to move around in the head, causing the injector bore - a precision reamed hole - to get damaged. If you catch it early enough, a new injector seal and installing the decoupler element will fix it.

It is possible someone had put in a new injector without a decoupler in #2, and when the dealer did another set of injectors, they did put them on. Run it hard and see how it responds.