Weird rpm at 100 kph

[Shaneus]

I have a stock VS Berlina, and normal rpm at 100kph is 1750rpm, now when I go down a hill at 100kph i found my car stays on 1250 for a second then to 1500, then back to 1250 ect. It keeps my car from going over 100 down a hill, but if I accelerate over 105 the problem goes away and the car speeds up down the hill.

I have only just noticed it happening, has anyone else seen or herd anything like this before.

If you need more information just ask, or you need clarity on something I have said.

Thank-you

 

[Immortality]

could possibly be that it's unlocking the converter and lets the engine return to idle so that it coasts down the hill and consumes less fuel. i have noticed something similar in the missus VS but it behaves normally so was never concerned with it

 

[Clutchy]

Was going to mention the converter locking and unlocking but ya beat me to it immortality.

 

[Chirpstr]

Is there a way to actually replace the torque converter? I know it just falls out pretty easy. Don't think it can be serviced but maybe replaced? Although if there was a tranny at the wreckers then chances are that the converter is cactus.
What do they do with the recon ones? And is there a way to slash the $1500 dollar mark by just replacing the converter?

Cheers

 

[Immortality]

you can replace a converter and they can be serviced, jsut that they gotta cut it to do it and then reweld it. not a cheap option. you should be able to get a replacement however. no idea on prices however

the converter locking and unlocking is normal, it's controlled by the PCM to gain max fuel economy depending on load/rpm/road speed etc

 

[Chirpstr]

Yeah well when I coast down a hill at around 95km-70km the revs jump up and down around 1500rpm, so is this a converter problem or is it a bad earth or something?
Thinking more towards a converter problem...also it slips abit in 3rd.
And the power button does nothing at all with this issue.
Yeah it would be a pain to fix if the converter is my problem, because it's welded. Probably cheaper getting a replacement tranny later, from the Quokka maybe...