Chug / kangaroo at start from cold

[Julian24110]

Since I’ve had it, my 3.0 E85 with 63k has always done something odd if I reverse immediately after starting from cold. It’s now started doing the same thing on pulling away in 1st from cold. However this stops as soon as the car is rolling and doesn’t do it again until the next cold start.

It’s hard to describe other than as the title says. The engine ‘chugs’ slightly, or sounds a bit like an idling touring car but only under load and only for the initial pull away. This does cause a little kangaroo effect.

As I say this is literally only the first few metres of movement, only when cold and not noticeable at idle.

Wondering if it’s VANOS related as this is the only job that hasn’t been done. Any ideas?

[rdm05z4]

If it is a manual might be an issue with the clutch? If you were in Australia based on title would say you have an extra passenger!

[mjennings23]

I've heard of similar in other BMWs can be caused by a bit of moisture around the spark plugs, which evaporates off quickly once the engine is running due to the heat in that area hence apparently fixing itself quickly.

[Julian24110]

Thanks, it’s definitely an engine thing rather than transmission. I like the spark plug theory, especially as that isn’t going to cost me

[Julian24110]

Today I tried idling the engine for 30-60 seconds before pulling away. Absolutely no chugging! Sounds like condensation is the cause.