Rough acceleration @ approx 2200rpm

[Witty9]

Hey everyone. Just wondering if anyone has this issue.
When engine is cold more so, when slowly increasing the revs, at approx 2200rpm, it get really rough and belts out heaps of smoke... Then when rpm passes approx 2400rpm, it increases rpm no worries - free of roughness etc.

Motor is 3.2, ml triton. Only 145k kms.

Any suggestions?

[Brett05]

try here for a start
viewtopic.php?f=39&t=7472
and here
viewtopic.php?f=39&t=2477
cheers
Brett

[Froggy]

Exactly the same symptoms as when mine blew an injector except it happened around 1800 for me.
Doesn't sound to me like carbon build up.

[coop1er]

swirl control valves / lower manifold clogged with carbon

[Witty9]

Thanks guys. Hope it's not a rooted injector.. What's the swirl control valve..? Might look at the lower manifold sensor though...

[GLRkenny]

Thanks guys. Hope it's not a rooted injector.. What's the swirl control valve..? Might look at the lower manifold sensor though...

Not the sensor, the actual manifold can get clogged with carbon, the swirl control valves are inside the lower manifold and stop working, see pics:

Clogged manifold


Same manifold cleaned


They swirl control is the butterflies in the middle

I should add that this car was running very rough around 2200-2500 and was fixed after cleaning the manifold