[Mike_B]

This only occurs in neutral or at very light loads, typically in low range when off road, I don't recall it happening in high range in normal driving.
When holding a steady 2000 RPM or just over that, the engine will momentarily cut back to idle, then continues as if nothing happened, can make driving slowly around the bush a bit jerky..

Anybody know what the cause is and how to fix it please?

I haven't done a search for this, wasn't sure what it might be under, if anyone knows of a relevant previous discussion please post a link.

Thanks in advance,
Mike

[Gwagensteve]

Air lock in the Idle speed control system - it's fed with coolant, and higher than the radiator. It's up on the throttle body.

I've had this problem in the past and I'm going to fit a bleed to the hoses that feed it.

Steve.

[royce]

you are holding the throttle open to get the 2000rpm?

how long is momentarily? I would go through the basics, loose intake pipes, shorting spark leads, loose wires

[Mike_B]

Gwagensteve wrote:

Air lock in the Idle speed control system - it's fed with coolant, and higher than the radiator. It's up on the throttle body.

I've had this problem in the past and I'm going to fit a bleed to the hoses that feed it.

Steve.

Thanks Steve,

I think that it has only been a problem since the thermostat was replaced as part of another operation to restore the vehicle to normal operation, so I will follow it up on the week end when I can have some time in the daylight ot work on it.
By the way, do you have any suggestions to remove the air lock?
Is it possible to bleed it out at one of the connections on the throttle body, by removing the hose temporarily, or will it come out by running the engine with radiator cap off, or...?

After that, if there is no improvement I can follow up on Royce's comments.

Thanks\Mike

[BlueSuzy]

What G16b?

Baleno = Tps

[Mike_B]

Apologies for the delay in reporting on this issue, I had to re-schedule when transfer case oil seals started leaking a bit too much, all sorted now.
Back to the original topic, I disconnected the coolant hose at the highest point and it had plenty of coolant in it, and didn't seem to have an air lock, so left it and went on to the TPS, which didn't test correctly, so I reset the TPS and then got some test results that were good. So far the Vit drives better after an, admittedly short, test drive it didn't have the momentary cutting back to idle from around 2000RPM when in neutral in the driveway, so I think I fixed it, thanks to all who gave feedback, really appreciate it.